Background: Early research describing the concept of intensity-modulated conformal radiotherapy (IMRT) was based on 7 to 9 beams to reach an adequate level of modulation. Nevertheless, its implementation demands signi...Background: Early research describing the concept of intensity-modulated conformal radiotherapy (IMRT) was based on 7 to 9 beams to reach an adequate level of modulation. Nevertheless, its implementation demands significant resources. Our objective was to compare the compliance and homogeneity of target dose distribution between simplified IMRT and 3D-CRT in patients with cervical cancer and to assess the clinical value of simplified IMRT. Materials and Methods: From 2016 to 2017, 17 patients with stage IIB - IIIC cervical cancer were treated with external beam radiotherapy using simplified IMRT (12 cases) or 3DCRT (05 cases) and brachytherapy. Prior to radiotherapy, CT scans were conducted to delineate the target volume. The clinical target volume (CTV) included the uterus, primary tumor, supravaginal portion of the cervix, paracervical tissue, common iliac, internal and external iliac lymph nodes, obturator, and pre sacral lymph nodes, and the surrounding tissues. If the lower vagina was involved, the target volume included the whole vagina. The planning target volume (PTV) included the CTV with 1 cm anteriorly and 0.5 cm in all other directions. The PTV received 95% of 45 Gy (1.8 Gy/25 fraction). Dose-volume histogram, conformity index, homogeneity index, and treatment time per fraction were compared. Results: The 3D-CRT plan was more homogeneous than the simplified IMRT plan, while the simplified IMRT plan was more conformal. The volume of small bowels that received high-dose radiation significantly increased with simplified IMRT compared to 3D-CRT. Treatment time per fraction was 6 and 13 minutes for 3D-CRT and simplified IMRT, respectively. Conclusion: The simplified IMRT treatment plan is technically and dosimetrically acceptable and an alternative to the classic 3D-CRT plan for cervical cancer. It provides better dose distribution than 3D-CRT. However, the 3D-CRT treatment plan significantly reduced the overall treatment time per fraction.展开更多
Background: The prognostic values of staging parameters require continual re?assessment amid changes in diag?nostic and therapeutic methods. This study aimed to identify the prognostic factors and failure patterns of ...Background: The prognostic values of staging parameters require continual re?assessment amid changes in diag?nostic and therapeutic methods. This study aimed to identify the prognostic factors and failure patterns of non?meta?static nasopharyngeal carcinoma(NPC) in the intensity?modulated radiotherapy(IMRT) era.Methods: We reviewed the data from 749 patients with newly diagnosed, biopsy?proven, non?metastatic NPC in our cancer center(South China, an NPC endemic area) between January 2003 and December 2007. All patients under?went magnetic resonance imaging(MRI) before receiving IMRT. The actuarial survival rates were estimated using the Kaplan–Meier method, and survival curves were compared using the log?rank test. Multivariate analyses with the Cox proportional hazards model were used to test for the independent prognostic factors by backward eliminating insigniicant explanatory variables.Results: The 5?year occurrence rates of local failure, regional failure, locoregional failure, and distant failure were 5.4, 3.0, 7.4, and 17.4%, respectively. The 5?year survival rates were as follows: local relapse?free survival, 94.6%; nodal relapse?free survival, 97.0%; distant metastasis?free survival, 82.6%; disease?free survival, 75.1%; and overall survival, 82.0%. Multivariate Cox regression analysis revealed that orbit involvement was the only signiicant prognostic fac?tor for local failure(P = 0.011). Parapharyngeal tumor extension, retropharyngeal lymph node involvement, and the laterality, longest diameter, and Ho's location of the cervical lymph nodes were signiicant prognostic factors for both distant failure and disease failure(all P < 0.05). Intracranial extension had signiicant prognostic value for distant failure(P = 0.040).Conclusions: The key failure pattern for NPC was distant metastasis in the IMRT era. With changes in diagnostic and therapeutic technologies as well as treatment modalities, the signiicant prognostic parameters for local control have also been altered substantially.展开更多
Background:In the era of intensity-modulated radiotherapy(IMRT),the role of neoadjuvant chemotherapy(NAC)for locoregionally advanced nasopharyngeal carcinoma(NPC)is under-evaluated.The aim of this study was to compare...Background:In the era of intensity-modulated radiotherapy(IMRT),the role of neoadjuvant chemotherapy(NAC)for locoregionally advanced nasopharyngeal carcinoma(NPC)is under-evaluated.The aim of this study was to compare the efficacy of NAC plus IMRT and concurrent chemoradiotherapy(CCRT)plus adjuvant chemotherapy(AC)on locoregionally advanced NPC.Methods:Between January 2004 and December 2008,240 cases of locoregionally advanced NPC confirmed by pathologic assessment in Sun Yat-sen University Cancer Center were reviewed.Of the 240 patients,117 received NAC followed by IMRT,and 123 were treated with CCRT plus AC.The NAC+IMRT group received a regimen that included cisplatin and 5-fluorouracil(5-FU).The CCRT+AC group received cisplatin concurrently with radiotherapy,and subsequently received adjuvant cisplatin and 5-FU.The survival rates were assessed by Kaplan-Meier analysis,and the survival curves were compared using a log-rank test.Multivariate analysis was conducted using the Cox proportional hazard regression model.Results:The 5-year overall survival(OS),locoregional relapse-free survival(LRRFS),distant metastasis-free survival(DMFS),and disease-free survival(DFS)were 78.0,87.9,79.0,and 69.8%,respectively,for the NAC+IMRT group and78.7,84.8,76.2,and 65.6%,respectively,for the CCRT+AC group.There were no significant differences in survival between the two groups.In multivariate analysis,age(<50 years vs.>50 years)and overall stage(Ⅲvs.Ⅳ)were found to be independent predictors for OS and DFS;furthermore,the overall stage was a significant prognostic factor for DMFS.Compared with the CCRT+AC protocol,the NAC+IMRT protocol significantly reduced the occurrence rates of grade 3-4 nausea-vomiting(6.5 vs.1.5%,P=0.023)and leukopenia(9.7 vs.0.8%,P=0.006).Conclusions:The treatment outcomes of the NAC+IMRT and CCRT+AC groups were similar.Distant metastasis remained the predominant mode of treatment failure.展开更多
Background: Gross target volume of primary tumor(GTV?P) is very important for the prognosis prediction of patients with nasopharyngeal carcinoma(NPC), but it is unknown whether the same is true for locally advanced NP...Background: Gross target volume of primary tumor(GTV?P) is very important for the prognosis prediction of patients with nasopharyngeal carcinoma(NPC), but it is unknown whether the same is true for locally advanced NPC patients treated with intensity?modulated radiotherapy(IMRT). This study aimed to clarify the prognostic value of tumor volume for patient with locally advanced NPC receiving IMRT and to ind a suitable cut?of value of GTV?P for prognosis prediction.Methods: Clinical data of 358 patients with locally advanced NPC who received IMRT were reviewed. Receiver oper?ating characteristic(ROC) curves were used to identify the cut?of values of GTV?P for the prediction of diferent end?points [overall survival(OS), local relapse?free survival(LRFS), distant metastasis?free survival(DMFS), and disease?free survival(DFS)] and to test the prognostic value of GTV?P when compared with that of the American Joint Committee on Cancer T staging system.Results: The 358 patients with locally advanced NPC were divided into two groups by the cut?of value of GTV?P as determined using ROC curves: 219(61.2%) patients with GTV?P ≤46.4 mL and 139(38.8%) with GTV?P >46.4 mL. The 3?year OS, LRFS, DMFS, and DFS rates were all higher in patients with GTV?P ≤46.4 mL than in those with GTV?P > 46.4 mL(all P < 0.05). Multivariate analysis indicated that GTV?P >46.4 mL was an independent unfavorable prognostic factor for patient survival. The ROC curve veriied that the predictive ability of GTV?P was superior to that of T category(P < 0.001). The cut?of values of GTV?P for the prediction of OS, LRFS, DMFS, and DFS were 46.4, 57.9, 75.4 and 46.4 mL, respectively.Conclusion: In patients with locally advanced NPC, GTV?P >46.4 mL is an independent unfavorable prognostic indi?cator for survival after IMRT, with a prognostic value superior to that of T category.展开更多
Background:For patients with nasopharyngeal carcinoma(NPC) who undergo re-irradiation with intensity-modulated radiotherapy(IMRT),lethal nasopharyngeal necrosis(LNN) is a severe late adverse event.The purpose of this ...Background:For patients with nasopharyngeal carcinoma(NPC) who undergo re-irradiation with intensity-modulated radiotherapy(IMRT),lethal nasopharyngeal necrosis(LNN) is a severe late adverse event.The purpose of this study was to identify risk factors for LNN and develop a model to predict LNN after radical re-irradiation with IMRT in patients with recurrent NPC.Methods:Patients who underwent radical re-irradiation with IMRT for locally recurrent NPC between March 2001 and December 2011 and who had no evidence of distant metastasis were included in this study.Clinical characteristics,including recurrent carcinoma conditions and dosimetric features,were evaluated as candidate risk factors for LNN.Logistic regression analysis was used to identify independent risk factors and construct the predictive scoring model.Results:Among 228 patients enrolled in this study,204 were at risk of developing LNN based on risk analysis.Of the 204 patients treated,31(15.2%) developed LNN.Logistic regression analysis showed that female sex(P = 0.008),necrosis before re-irradiation(P = 0.008),accumulated total prescription dose to the gross tumor volume(GTV) ≥ 145.5 Gy(P = 0.043),and recurrent tumor volume >25.38 cm3(P = 0.009) were independent risk factors for LNN.A model to predict LNN was then constructed that included these four independent risk factors.Conclusions:A model that includes sex,necrosis before re-irradiation,accumulated total prescription dose to GTV,and recurrent tumor volume can effectively predict the risk of developing LNN in NPC patients who undergo radical re-irradiation with IMRT.展开更多
AIM: To investigate the toxicity and response of intensity-modulated radiotherapy schedule intensified with a simultaneous integrated boost in anal canal cancer.METHODS: From March 2009 to March 2014, we retrospective...AIM: To investigate the toxicity and response of intensity-modulated radiotherapy schedule intensified with a simultaneous integrated boost in anal canal cancer.METHODS: From March 2009 to March 2014, we retrospectively analyzed 41 consecutive patients treated with intensity-modulated radiotherapy(IMRT) and concurrent chemotherapy for anal canal squamous cell carcinoma at our center. Radiotherapy was delivered via simultaneous integrated boost(SIB) technique by helical tomotherapy, and doses were adapted to two clinical target volumes according to the tumor-nodemetastasis(TNM) stage: 50.6 Gy and 41.4 Gy in 23 fractions in T1N0, 52.8 Gy and 43.2 Gy in 24 fractionsin T2N0, and 55 Gy and 45 Gy in 25 fractions in all patients with N positive and/or ≥ T3, respectively, to planning target volumes 1 and 2. The most common chemotherapy regimen was 5-fluorouracil and mitomycin-based. Human papilloma virus(HPV) p16 expression was performed by immunohistochemistry and evaluated in the majority of patients. Acute and late toxicity was scored according to CTCAe v 3.0 and RTOG scales.RESULTS: The median follow-up was 30 mo(range:12-71). Median age was 63 years(range 32-84). The stage of disease was: stage Ⅰ in 2 patients, stage Ⅱin 13 patients, stage ⅢA in 12 patients, and stage ⅢB in 14 patients, respectively. Two patients were known to be HIV positive(4.9%). HPV p16 expression status was positive in 29/34(85.3%) patients. The 4-year progression-free survival and overall survival in HPVpositive patients were 78% and 92%, respectively.Acute grade 3 skin and gastrointestinal toxicities were reported in 5% and 7.3% of patients, respectively;patients' compliance to the treatment was good due to a low occurrence of severe acute toxicity, although treatment interruptions due to toxicity were required in 7.3% of patients. At 6 mo from end of treatment,36/40(90%) patients obtained complete response;during follow-up, 5(13.8%) patients presented with disease progression(local or systemic).CONCLUSION: In our experience, intensified SIBIMRT with chemotherapy is very feasible in clinical practice, with excellent results in terms of overall survival and local control.展开更多
Background:Nasopharyngeal carcinoma(NPC) shows a high proportion of lymph node metastasis,and treatment guidelines have been developed for positive nodes.However,no irradiation guidelines have been proposed for patien...Background:Nasopharyngeal carcinoma(NPC) shows a high proportion of lymph node metastasis,and treatment guidelines have been developed for positive nodes.However,no irradiation guidelines have been proposed for patients with enlarged neck lymph nodes(ENLNs) that do not meet the radiological criteria of 10 mm in diameter for positive lymph nodes.This study aimed to determine the prognostic value and radiation dose for ENLNs in NO-category NPC patients treated with intensity-modulated radiotherapy(IMRT).Methods:We reviewed the medical data of 251 patients with non-metastatic,NO-category NPC treated with IMRT.Receiver operating characteristic curves were used to calculate the cut-off value of the ENLN diameter for the prediction of disease failure.The biological equivalent dose(BED) for ENLNs was calculated.Patient survival was compared between the small and large ENLN groups.Independent prognostic factors were identified using the Cox proportional hazards model.Results:The estimated 4-year regional relapse-free survival rate was higher in patients with ENLNs ≥5.5 mm than in those with ENLNs <5.5 mm(100%vs.98.8%,P=0.049),whereas disease-free,overall,and distant metastasis-free survival rates were similar between the two groups.After adjusting for various factors,ENLN diameter was not identified as an independent prognostic factor(P > 0.05 for all survival rates).In the subgroup analysis,patients receiving BED ≥72 Gy had a similar prognosis as patients receiving BED <72 Gy in both the small and large ENLN groups.The multivariate analysis also confirmed that BED≥72 Gy was not associated with significantly improved prognosis in patients with NO-category NPC.Conclusions:A BED of 72 Gy to ENLNs is considerably sufficient to provide a clinical benefit to patients with NO-category NPC.Prospective studies are warranted to validate the findings in the present study.展开更多
Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emiss...Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emission tomography/computed tomography(PET/CT).The present study aimed to evaluate the diagnostic values of PET/CT in identifying metastasis in SCLNs in NPC patients.Methods: Magnetic resonance images(MRI) and PET/CT scans for 470 patients with newly diagnosed, non-distant metastatic NPC were analyzed. Metastatic rates of SCLNs were defined by the positive number of SCLNs on PET/CT scans and total number of SCLNs on MRI scans. Receiver operating characteristic curve was applied to compare PET/CT-determined stage with MRI-determined stage.Results: In total, 2082 SCLNs were identified, with 808(38.8%) ≥ 5 and < 6 mm in diameter(group A), 526(25.3%)≥ 6 and < 7 mm in diameter(group B),374(18.0%)≥ 7 and < 8 mm in diameter(group C), 237(11.4%) ≥8 and<9 mm in diameter(group D),and 137(6.5%) ≥ 9 and <10 mm in diameter(group E).The overall metastatic rates examined by using PET/CT for groups A, B,C,D, and E were 3.5%, 8.0%, 31.3%, 60.0%, and 83.9%, respectively(P< 0.001). In level IV/Vb, the metastatic rate for nodes ≥ 8 mm was 84.6%. PET/CT examination resulted in modification of N category and overall stage for 135(28.7%) and 46(9.8%) patients, respectively. The areas under curve of MRIdetermined and PET/CT-determined overall stage were 0.659 and 0.704 for predicting overall survival, 0.661 and 0.711 for predicting distant metastasis-free survival, and 0.636 and 0.663 for predicting disease-free survival.Conclusions: PET/CT was more effective than MRI in identifying metastatic SCLNs, and the radiologic diagnostic criteria for metastatic lymph nodes in level IV/Vb should be re-defined.展开更多
Objective: The purpose of this study was to investigate the impact of intensity modulated radiotherapy (IMRT) on surface doses for brain, abdomen and pelvis deep located tumors treated with 6 MV photon and to evaluate...Objective: The purpose of this study was to investigate the impact of intensity modulated radiotherapy (IMRT) on surface doses for brain, abdomen and pelvis deep located tumors treated with 6 MV photon and to evaluate the skin dose calculation accuracy of the XIO 4.04 treatment planning system. Methods: More investigations for the influences of IMRT on skin doses would increase its applications for many treatment sites. Measuring skin doses in real treatment situations would reduce the uncertainty of skin dose prediction. In this work a pediatric human phantom was covered by a layer of 1 mm bolus at three treatment sites and thermoluminescent dosimeter (TLD) chips were inserted into the bolus at each treatment site before CT scan. Two different treatment plans [three-dimensional conformal radiation therapy (3DCRT) and IMRT] for each treatment sites were performed on XIO 4.04 treatment planning system using superposition algorism. Results: The results showed that the surface doses for 3DCRT were higher than the surface doses in IMRT by 1.6%, 2.5% and 3.2% for brain, abdomen and pelvis sites respectively. There was good agreement between measured and calculated surface doses, where the calculated surface dose was 15.5% for brain tumor calculated with 3DCRT whereas the measured surface dose was 12.1%. For abdomen site the calculated surface dose for IMRT treatment plan was 16.5% whereas the measured surface dose was 12.6%. Conclusion: The skin dose in IMRT for deep seated tumors is lower than that in 3DCRT which is another advantage for the IMRT. The TLD readings showed that the difference between the calculated and measured point dose is negligible. The superposition calculation algorism of the XIO 4.04 treatment planning system modeled the superficial dose well.展开更多
Objective:This study was to compare 5 field conformal technique to the intensity modulated radiotherapy (IMRT) 8 fields technique in boosting locally advanced cancer cervix cases after external beam radiotherapy with ...Objective:This study was to compare 5 field conformal technique to the intensity modulated radiotherapy (IMRT) 8 fields technique in boosting locally advanced cancer cervix cases after external beam radiotherapy with respect to target volume coverage and dose to normal tissues. Methods:We conducted a single institutional comparative dosimetric analysis of 10 patients with cancer cervix who was presented to radiotherapy department in National Cancer Institute, Cairo in period between June 2012 to September 2012 and received a CRT boost in the place of planned brachytherapy after large field pelvic radiotherapy (PRT) with concurrent chemotherapy were retrospectively identified. All tumors were situated in the low central pelvis. Two plans were done for every patient; one using the 8 fields IMRT and the second one using 5 fields' 3DCRT the two techniques were then compared using dose volume histogram (DVH) analysis for the PTV, bladder, rectum and both femoral heads. Results:Comparing different DVHs, it was found that the planning target volume (PTV) was adequately covered in both plans while it was demonstrates that the 8 fields IMRT technique carried less doses reaching OARs (rectum, bladder, both femoral heads). Conclusion:From the present study, it is concluded that IMRT technique spared more efficiently OARs than CRT technique but both techniques covered the PTV adequately so whenever possible IMRT technique should be used.展开更多
Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty pati...Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty patients with middle and advanced stage NSCLC were randomized into two groups. Forty patients were underwent sequential therapy and other 40 patients were underwent concurrent therapy. IMRT was used in radiotherapy and NP regimen of vinorelbine+cispatin (NP) was used in chemotherapy. Results: (1) The overall response (CR+PR) rate was 75% in concurrent group and 45% in sequential group (P<0.05); (2) The treatment courses were 84 days and 140 days for concurrent group and sequential group respectively (P<0.05); (3) One-year survival rate in concurrent group was 72.4% and 52.3% in sequential group respectively; (4) The toxic effects can be tolerable by all of patients. Conclusion: The concurrent chemo-radiotherapy has better overall re- sponse, one-year survival rate and shorter treatment course than the sequential chemo-radiotherapy, so it is a better method for the treatment of middle and advanced stage NSCLC, but the long term survival rate will be studied.展开更多
Objective： To evaluate if the combination of both prone position on a belly board and intensity-modulated radiotherapy （IMRT） further reduces the radiation dose to small bowel in pelvic RT for gynecologic malignanc...Objective： To evaluate if the combination of both prone position on a belly board and intensity-modulated radiotherapy （IMRT） further reduces the radiation dose to small bowel in pelvic RT for gynecologic malignancies. Methods： Conformal pelvic RT plans were computed in 13 patients with gynecologic malignancies who had pre-existing planning computed tomography （CT） scans in both the supine position and prone position on a belly board. There were 10 cervical cancer and 3 endometrial cancer patients. A limited arc technique （180° arc length） and an extended arc technique （340° arc length） were used in IMRT plans. Normal tissue regions of interest （ROI） included small bowel, large bowel and bladder. Dose and volume for normal tissue structures were traced and compared between supine and prone plans using the paired t-test. Results： For the limited arc technique, prone position using a belly board device improved small bowel sparing. Analysis of the results showed a 12~26 Gy reduction of volume of small bowel irradiation compared to the supine position. With the extended arc technique, there was no obvious radiation reduction in the prone position. Large bowel and bladder dose showed no significant differences between prone and supine position with either technique. Conclusion： Prone positioning on a belly board decreases the small bowel dose in gynecologic pelvic IMRT, and the magnitude of improvement depended on the limited arc IMRT technique used.展开更多
Surgical excision and postoperative radiotherapy are widely accepted therapeutic modalities for sinonasal teratocarcinosarcoma （SNTCS）. Previous studies have shown that intensity-modulated radiation therapy （IMRT）...Surgical excision and postoperative radiotherapy are widely accepted therapeutic modalities for sinonasal teratocarcinosarcoma （SNTCS）. Previous studies have shown that intensity-modulated radiation therapy （IMRT） is safe and effective for the treatment of some sinonasal malignancies. We hypothesize that use of IMRT for SNTCS may result in clinical benefits. We report here two cases of SNTCS that were treated by IMRT. One patient was given extensive IMRT involving elective neck irradiation. Follow-up examinations revealed no recurrence and metastasis 3.5 years after IMRT. Another patient simultaneously suffered from multiple systematical diseases and was administered involved-field radiotherapy. He was found to have a marginal recurrence during the follow up and eventually died 8 months after disease diagnosis. It was suggested in this study that appropriate use of IMRT for the treatment of SNTCS may achieve excellent local control.展开更多
Objective: Juvenile Nasopharyngeal Angiofibroma (JNA) is a benign neoplasm with a high vascularity component, greater craniofacial involvement in adolescent patients, and aggressive local behaviour. In unresectable pa...Objective: Juvenile Nasopharyngeal Angiofibroma (JNA) is a benign neoplasm with a high vascularity component, greater craniofacial involvement in adolescent patients, and aggressive local behaviour. In unresectable patients, radiotherapy is a therapeutic option for local control. Our aim in this study was to analyze the clinical benefit and local control provided by two modalities of radiotherapy: the Three-Dimensional Conformal (3DC) technique and volumetric modulated arc therapy (VMAT), applied to pediatric patients with JNA considered unresectable and non-recurrent. Methods: In retrospective study, the information was recorded from pediatric patients with a diagnosis of non-recurrent and unresectable JNA treated with radiotherapy at the Oncology Hospital of the National Medical Center SXXI of Mexico City, from March 2010 to March 2021. Radiotherapy management and its association with clinical outcomes of tumour control, and symptoms were assessed. In addition, an evaluation of acute and chronic toxicity was performed. Results: It was found that the median age was 14 years. 9 patients (37.5%) underwent 3DC and 15 (62.5%) VMAT. In terms of local control, and progression-free survival, we did not find significant difference between radiotherapy modalities (p ≤ 0.57). Acute toxicity for both modalities presented statistical differences for radio epithelitis (p = 0.03). Only Grade I and II radiation-induced acute toxicity was observed. Regarding chronic toxicity, statistical significance was observed for craniofacial hypoplasia, in relation to its absence in the VMAT group (p = 0.001). Conclusion: The VMAT presents improvements in dosimetry parameters that improve patient toxicity. In both techniques adequate tumour control was observed, however, the rarity of the disease is a limitation to establish the most appropriate therapeutic technique.展开更多
AIM： To compare the volumetric-modulated arc ther- apy （VMAT） plans with conventional sliding window intensity-modulated radiotherapy （c-IMRT） plans in esophageal cancer （EC）. METHODS： Twenty patients with EC ...AIM： To compare the volumetric-modulated arc ther- apy （VMAT） plans with conventional sliding window intensity-modulated radiotherapy （c-IMRT） plans in esophageal cancer （EC）. METHODS： Twenty patients with EC were selected, including 5 cases located in the cervical, the upper, the middle and the lower thorax, respectively. Five plans were generated with the eclipse planning sys- tem： three using c-IMRT with 5 fields （5F）, 7 fields （7F） and 9 fields （gF）, and two using VMAT with a single arc （1A） and double arcs （2A）. The treatment plans were designed to deliver a dose of 60 Gy to the plan-ning target volume （PTV） with the same constrains in a 2.0 Gy daily fraction, 5 d a week. Plans were normal- ized to 95% of the PTV that received 100% of the pre- scribed dose. We examined the dose-volume histogram parameters of PTV and the organs at risk （OAR） such as lungs, spinal cord and heart. Monitor units （MU） and normal tissue complication probability （NTCP） of OAR were also reported. RESULTS： Both c-IMRT and VMAT plans resulted in abundant dose coverage of PTV for EC of different Io- cations. The dose conformity to PTV was improved as the number of field in c-IMRT or rotating arc in VMAT was increased. The doses to PTV and OAR in VMAT plans were not statistically different in comparison with c-IMRT plans, with the following exceptions： in cervical and upper thoracic EC, the conformity index （CI） was higher in VMAT （1A 0.78 and 2A 0.8） than in c-IMRT （5F 0.62, 7F 0.66 and 9F 0.73） and homogeneity was slightly better in c-IMRT （7F 1.09 and 9F 1.07） than in VMAT （1A 1,1 and 2A 1.09）, Lung V30 was lower in VMAT （1A 12.52 and 2A 12.29） than in c-IMRT （7F 14.35 and 9F 14.81）. The humeral head doses were significantly increased in VMAT as against c-IMRT. In the middle and lower thoracic EC, CI in VMAT （1A 0.76 and 2A 0.74） was higher than in c-IMRT （5F 0.63 Gy and 7F 0.67 Gy）, and homogeneity was almost similar between VMAT and c-IMRT. V20 （2A 21.49 Gy vs 7F 24.59 Gy and 9F 24.16 Gy） and V30 （2A 9.73 Gy vs 5F 12.61 Gy, 7F 11.5 Gy and 9F 11.37 Gy） of lungs in VMAT were lower than in c-IMRT, but low doses to lungs （V5 and Vl0） were increased. V30 （1A 48.12 Gy vs 5F 59.2 Gy, 7F 58.59 Gy and 9F 57.2 Gy）, V40 and V50 of heart in VMAT was lower than in c-IMRT. MUs in VMAT plans were significantly reduced in comparison with c-IMRT, maximum doses to the spinal cord and mean doses of lungs were similar between the two techniques. NTCP of spinal cord was 0 for all cases. NTCP of lungs and heart in VMAT were lower than in c-IMRT. The advantage of VMAT plan was enhanced by doubling the arc. CONCLUSION： Compared with c-IMRT, VMAT, especial- ly the 2A, slightly improves the OAR dose sparing, such as lungs and heart, and reduces NTCP and MU with a better PTV coverage.展开更多
AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT an...AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT and 42 VMAT).Dose were 63.8 Gy(HT)and 63.2 Gy(VMAT)in the tumour bed,52.2 Gy in the breast,50.4 Gy in supraclavicular nodes(SCN)and internal mammary chain(IMC)with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions.Margins to particle tracking velocimetry were greater in the VMAT cohort(7 mm vs 5 mm).RESULTS For the HT cohort,the coverage of clinical target volumes was as follows:Tumour bed:99.4%±2.4%;breast:98.4%±4.3%;SCN:99.5%±1.2%;IMC:96.5%±13.9%.For the VMAT cohort,the coverage was as follows:Tumour bed:99.7%±0.5%,breast:99.3%±0.7%;SCN:99.6%±1.4%;IMC:99.3%±3%.For ipsilateral lung,Dmean and V20 were 13.6±1.2 Gy,21.1%±5%(HT)and 13.6±1.4 Gy,20.1%±3.2%(VMAT).Dmean and V30 of the heart were 7.4±1.4 Gy,1%±1%(HT)and 10.3±4.2 Gy,2.5%±3.9%(VMAT).For controlateral breast Dmean was 3.6±0.2 Gy(HT)and 4.6±0.9 Gy(VMAT).Acute skin toxicity grade 3 was 5%in the two cohorts.CONCLUSION HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance.A longer follow-up is needed to assess the impact of low doses to healthy tissues.展开更多
Objective: A dosimetric study was performed to evaluate the performance of volumetric modulated arc radiotherapy with RapidArc on locally advanced nasopharyngeal carcinoma (NPC). Methods: The CT scan data sets of 20 p...Objective: A dosimetric study was performed to evaluate the performance of volumetric modulated arc radiotherapy with RapidArc on locally advanced nasopharyngeal carcinoma (NPC). Methods: The CT scan data sets of 20 patients of locally advanced NPC were selected randomly. The plans were managed using volumetric modulated arc with RapidArc and fixed nine-field coplanar dynamic intensity-modulated radiotherapy (IMRT) for these patients. The dosimetry of the planning target volumes (PTV), the organs at risk (OARs) and the healthy tissue were evaluated. The dose prescription was set to 70 Gy to the primary tumor and 60 Gy to the clinical target volumes (CTV) in 33 fractions. Each fraction applied daily, five fractions per week. The monitor unit (MU) values and the delivery time were scored to evaluate the expected treatment efficiency. Results: Both techniques had reached clinical treatment’s requirement. The mean dose (Dmean), maximum dose (Dmax) and minimum dose (Dmin) in RapidArc and fixed field IMRT for PTV were 68.4±0.6 Gy, 74.8±0.9 Gy and 56.8±1.1 Gy; and 67.6±0.6 Gy, 73.8±0.4 Gy and 57.5±0.6 Gy (P<0.05), respectively. Homogeneity index was 78.85±1.29 in RapidArc and 80.34±0.54 (P<0.05) in IMRT. The conformity index (CI: 95%) was 0.78±0.01 for both techniques (P>0.05). Compared to IMRT, RapidArc allowed a reduction of Dmean to the brain stem, mandible and optic nerves of 14.1% (P<0.05), 5.6% (P<0.05) and 12.2% (P<0.05), respectively. For the healthy tissue and the whole absorbed dose, Dmean of RapidArc was reduced by 3.6% (P<0.05), and 3.7% (P<0.05), respectively. The Dmean to the parotids, the spinal cord and the lens had no statistical difference among them. The mean MU values of RapidArc and IMRT were 550 and 1,379. The mean treatment time of RapidArc and IMRT was 165 s and 447 s. Compared to IMRT, the delivery time and the MU values of RapidArc were reduced by 63% and 60%, respectively. Conclusion: For locally advanced NPC, both RapidArc and IMRT reached the clinic requirement. The target volume coverage was similar for the different techniques. The RapidArc technique showed some improvements in OARs and other tissue sparing while using reduced MUs and delivery time.展开更多
Objective This study evaluated the dosimetric consequences of selective partial salivary gland sparing during intensity-modulated radiotherapy(IMRT) for patients with nasopharyngeal carcinoma(NPC).Methods Ten patients...Objective This study evaluated the dosimetric consequences of selective partial salivary gland sparing during intensity-modulated radiotherapy(IMRT) for patients with nasopharyngeal carcinoma(NPC).Methods Ten patients with NPC were enrolled in the study.Two IMRT plans were produced for each patient:conventional(control) and partial salivary glands-sparing(treatment),with dose constraints to the entire parotid glands or partial salivary glands(including the parotid and submandibular glands,delineated with the adjacent distance of at least 0.5 cm between the glands and PTV,the planning target volume) in planning,respectively.Dosimetric parameters were compared between the two plans,including the V_(110%),V_(100%),V_(95%)(the volume covered by more than 110%,100%,or 95% of the prescribed dose),Dmin(the minimum dose) of PTV,homogeneity index(HI),conformity index(CI),and the mean dose and percentage of the volume receiving 30 Gy or more(V_(30)) for the parotid glands and submandibular glands.Results Treatment plans had significantly lower mean doses and V_(30) to both the entire parotid glands and partial parotid glands than those in control plans.The mean doses to the partial submandibular glands were also significantly lower in treatment plans than in control plans.The PTV coverage was comparable between the two plans,as indicated by V_(100%),V_(95%),Dmin,CI,and HI.The doses to critical structures,including brainstem and spinal cord,were slightly but not significantly higher in treatment plans than in control plans.Conclusion A selective partial salivary gland-sparing approach reduces the doses to parotid and submandibular glands during IMRT,which may decrease the risk of post-radiation xerostomia while not compromising target dose coverage in patients with NPC.展开更多
文摘Background: Early research describing the concept of intensity-modulated conformal radiotherapy (IMRT) was based on 7 to 9 beams to reach an adequate level of modulation. Nevertheless, its implementation demands significant resources. Our objective was to compare the compliance and homogeneity of target dose distribution between simplified IMRT and 3D-CRT in patients with cervical cancer and to assess the clinical value of simplified IMRT. Materials and Methods: From 2016 to 2017, 17 patients with stage IIB - IIIC cervical cancer were treated with external beam radiotherapy using simplified IMRT (12 cases) or 3DCRT (05 cases) and brachytherapy. Prior to radiotherapy, CT scans were conducted to delineate the target volume. The clinical target volume (CTV) included the uterus, primary tumor, supravaginal portion of the cervix, paracervical tissue, common iliac, internal and external iliac lymph nodes, obturator, and pre sacral lymph nodes, and the surrounding tissues. If the lower vagina was involved, the target volume included the whole vagina. The planning target volume (PTV) included the CTV with 1 cm anteriorly and 0.5 cm in all other directions. The PTV received 95% of 45 Gy (1.8 Gy/25 fraction). Dose-volume histogram, conformity index, homogeneity index, and treatment time per fraction were compared. Results: The 3D-CRT plan was more homogeneous than the simplified IMRT plan, while the simplified IMRT plan was more conformal. The volume of small bowels that received high-dose radiation significantly increased with simplified IMRT compared to 3D-CRT. Treatment time per fraction was 6 and 13 minutes for 3D-CRT and simplified IMRT, respectively. Conclusion: The simplified IMRT treatment plan is technically and dosimetrically acceptable and an alternative to the classic 3D-CRT plan for cervical cancer. It provides better dose distribution than 3D-CRT. However, the 3D-CRT treatment plan significantly reduced the overall treatment time per fraction.
基金supported by grants from the Key Laboratory Construction Project of Guangzhou City,China (121800085)the Health & Medical Collaborative Innovation Project of Guangzhou City,China (201400000001)+2 种基金the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (2014BAI09B10)the National Natural Science Foundation of China (81201746)the Planned Science and Technology Project of Guangdong Province,China (2013B020400004)
文摘Background: The prognostic values of staging parameters require continual re?assessment amid changes in diag?nostic and therapeutic methods. This study aimed to identify the prognostic factors and failure patterns of non?meta?static nasopharyngeal carcinoma(NPC) in the intensity?modulated radiotherapy(IMRT) era.Methods: We reviewed the data from 749 patients with newly diagnosed, biopsy?proven, non?metastatic NPC in our cancer center(South China, an NPC endemic area) between January 2003 and December 2007. All patients under?went magnetic resonance imaging(MRI) before receiving IMRT. The actuarial survival rates were estimated using the Kaplan–Meier method, and survival curves were compared using the log?rank test. Multivariate analyses with the Cox proportional hazards model were used to test for the independent prognostic factors by backward eliminating insigniicant explanatory variables.Results: The 5?year occurrence rates of local failure, regional failure, locoregional failure, and distant failure were 5.4, 3.0, 7.4, and 17.4%, respectively. The 5?year survival rates were as follows: local relapse?free survival, 94.6%; nodal relapse?free survival, 97.0%; distant metastasis?free survival, 82.6%; disease?free survival, 75.1%; and overall survival, 82.0%. Multivariate Cox regression analysis revealed that orbit involvement was the only signiicant prognostic fac?tor for local failure(P = 0.011). Parapharyngeal tumor extension, retropharyngeal lymph node involvement, and the laterality, longest diameter, and Ho's location of the cervical lymph nodes were signiicant prognostic factors for both distant failure and disease failure(all P < 0.05). Intracranial extension had signiicant prognostic value for distant failure(P = 0.040).Conclusions: The key failure pattern for NPC was distant metastasis in the IMRT era. With changes in diagnostic and therapeutic technologies as well as treatment modalities, the signiicant prognostic parameters for local control have also been altered substantially.
基金supported by grants from Sun Yat-sen University Clinical Research 5010 Program(No.2015010)the Fundamental Research Funds for the Central Universities(No.15ykpy36)Clinical Research of Special Funds of Wu Jieping Medical Foundation(no.320.6750.14270)
文摘Background:In the era of intensity-modulated radiotherapy(IMRT),the role of neoadjuvant chemotherapy(NAC)for locoregionally advanced nasopharyngeal carcinoma(NPC)is under-evaluated.The aim of this study was to compare the efficacy of NAC plus IMRT and concurrent chemoradiotherapy(CCRT)plus adjuvant chemotherapy(AC)on locoregionally advanced NPC.Methods:Between January 2004 and December 2008,240 cases of locoregionally advanced NPC confirmed by pathologic assessment in Sun Yat-sen University Cancer Center were reviewed.Of the 240 patients,117 received NAC followed by IMRT,and 123 were treated with CCRT plus AC.The NAC+IMRT group received a regimen that included cisplatin and 5-fluorouracil(5-FU).The CCRT+AC group received cisplatin concurrently with radiotherapy,and subsequently received adjuvant cisplatin and 5-FU.The survival rates were assessed by Kaplan-Meier analysis,and the survival curves were compared using a log-rank test.Multivariate analysis was conducted using the Cox proportional hazard regression model.Results:The 5-year overall survival(OS),locoregional relapse-free survival(LRRFS),distant metastasis-free survival(DMFS),and disease-free survival(DFS)were 78.0,87.9,79.0,and 69.8%,respectively,for the NAC+IMRT group and78.7,84.8,76.2,and 65.6%,respectively,for the CCRT+AC group.There were no significant differences in survival between the two groups.In multivariate analysis,age(<50 years vs.>50 years)and overall stage(Ⅲvs.Ⅳ)were found to be independent predictors for OS and DFS;furthermore,the overall stage was a significant prognostic factor for DMFS.Compared with the CCRT+AC protocol,the NAC+IMRT protocol significantly reduced the occurrence rates of grade 3-4 nausea-vomiting(6.5 vs.1.5%,P=0.023)and leukopenia(9.7 vs.0.8%,P=0.006).Conclusions:The treatment outcomes of the NAC+IMRT and CCRT+AC groups were similar.Distant metastasis remained the predominant mode of treatment failure.
基金supported by the National Natural Science Foundation of China (No.81372792)
文摘Background: Gross target volume of primary tumor(GTV?P) is very important for the prognosis prediction of patients with nasopharyngeal carcinoma(NPC), but it is unknown whether the same is true for locally advanced NPC patients treated with intensity?modulated radiotherapy(IMRT). This study aimed to clarify the prognostic value of tumor volume for patient with locally advanced NPC receiving IMRT and to ind a suitable cut?of value of GTV?P for prognosis prediction.Methods: Clinical data of 358 patients with locally advanced NPC who received IMRT were reviewed. Receiver oper?ating characteristic(ROC) curves were used to identify the cut?of values of GTV?P for the prediction of diferent end?points [overall survival(OS), local relapse?free survival(LRFS), distant metastasis?free survival(DMFS), and disease?free survival(DFS)] and to test the prognostic value of GTV?P when compared with that of the American Joint Committee on Cancer T staging system.Results: The 358 patients with locally advanced NPC were divided into two groups by the cut?of value of GTV?P as determined using ROC curves: 219(61.2%) patients with GTV?P ≤46.4 mL and 139(38.8%) with GTV?P >46.4 mL. The 3?year OS, LRFS, DMFS, and DFS rates were all higher in patients with GTV?P ≤46.4 mL than in those with GTV?P > 46.4 mL(all P < 0.05). Multivariate analysis indicated that GTV?P >46.4 mL was an independent unfavorable prognostic factor for patient survival. The ROC curve veriied that the predictive ability of GTV?P was superior to that of T category(P < 0.001). The cut?of values of GTV?P for the prediction of OS, LRFS, DMFS, and DFS were 46.4, 57.9, 75.4 and 46.4 mL, respectively.Conclusion: In patients with locally advanced NPC, GTV?P >46.4 mL is an independent unfavorable prognostic indi?cator for survival after IMRT, with a prognostic value superior to that of T category.
基金supported by the National Natural Science Foundation of China(No.81472525 and 81572665)the Science and Technology Planning Project of Guangdong Province,China(No.2014A050503033)
文摘Background:For patients with nasopharyngeal carcinoma(NPC) who undergo re-irradiation with intensity-modulated radiotherapy(IMRT),lethal nasopharyngeal necrosis(LNN) is a severe late adverse event.The purpose of this study was to identify risk factors for LNN and develop a model to predict LNN after radical re-irradiation with IMRT in patients with recurrent NPC.Methods:Patients who underwent radical re-irradiation with IMRT for locally recurrent NPC between March 2001 and December 2011 and who had no evidence of distant metastasis were included in this study.Clinical characteristics,including recurrent carcinoma conditions and dosimetric features,were evaluated as candidate risk factors for LNN.Logistic regression analysis was used to identify independent risk factors and construct the predictive scoring model.Results:Among 228 patients enrolled in this study,204 were at risk of developing LNN based on risk analysis.Of the 204 patients treated,31(15.2%) developed LNN.Logistic regression analysis showed that female sex(P = 0.008),necrosis before re-irradiation(P = 0.008),accumulated total prescription dose to the gross tumor volume(GTV) ≥ 145.5 Gy(P = 0.043),and recurrent tumor volume >25.38 cm3(P = 0.009) were independent risk factors for LNN.A model to predict LNN was then constructed that included these four independent risk factors.Conclusions:A model that includes sex,necrosis before re-irradiation,accumulated total prescription dose to GTV,and recurrent tumor volume can effectively predict the risk of developing LNN in NPC patients who undergo radical re-irradiation with IMRT.
文摘AIM: To investigate the toxicity and response of intensity-modulated radiotherapy schedule intensified with a simultaneous integrated boost in anal canal cancer.METHODS: From March 2009 to March 2014, we retrospectively analyzed 41 consecutive patients treated with intensity-modulated radiotherapy(IMRT) and concurrent chemotherapy for anal canal squamous cell carcinoma at our center. Radiotherapy was delivered via simultaneous integrated boost(SIB) technique by helical tomotherapy, and doses were adapted to two clinical target volumes according to the tumor-nodemetastasis(TNM) stage: 50.6 Gy and 41.4 Gy in 23 fractions in T1N0, 52.8 Gy and 43.2 Gy in 24 fractionsin T2N0, and 55 Gy and 45 Gy in 25 fractions in all patients with N positive and/or ≥ T3, respectively, to planning target volumes 1 and 2. The most common chemotherapy regimen was 5-fluorouracil and mitomycin-based. Human papilloma virus(HPV) p16 expression was performed by immunohistochemistry and evaluated in the majority of patients. Acute and late toxicity was scored according to CTCAe v 3.0 and RTOG scales.RESULTS: The median follow-up was 30 mo(range:12-71). Median age was 63 years(range 32-84). The stage of disease was: stage Ⅰ in 2 patients, stage Ⅱin 13 patients, stage ⅢA in 12 patients, and stage ⅢB in 14 patients, respectively. Two patients were known to be HIV positive(4.9%). HPV p16 expression status was positive in 29/34(85.3%) patients. The 4-year progression-free survival and overall survival in HPVpositive patients were 78% and 92%, respectively.Acute grade 3 skin and gastrointestinal toxicities were reported in 5% and 7.3% of patients, respectively;patients' compliance to the treatment was good due to a low occurrence of severe acute toxicity, although treatment interruptions due to toxicity were required in 7.3% of patients. At 6 mo from end of treatment,36/40(90%) patients obtained complete response;during follow-up, 5(13.8%) patients presented with disease progression(local or systemic).CONCLUSION: In our experience, intensified SIBIMRT with chemotherapy is very feasible in clinical practice, with excellent results in terms of overall survival and local control.
基金supported by grants from the Health & Medical Collaborative Innovation Project of Guangzhou City,China(No.201400000001)the Sun Yat-sen University Clinical Research 5010 Program(No.2012011)+1 种基金the Science and Technology Project of Guangzhou City,China(No.14570006)the Planned Science and Technology Project of Guangdong Province,China(No. 2013B020400004)
文摘Background:Nasopharyngeal carcinoma(NPC) shows a high proportion of lymph node metastasis,and treatment guidelines have been developed for positive nodes.However,no irradiation guidelines have been proposed for patients with enlarged neck lymph nodes(ENLNs) that do not meet the radiological criteria of 10 mm in diameter for positive lymph nodes.This study aimed to determine the prognostic value and radiation dose for ENLNs in NO-category NPC patients treated with intensity-modulated radiotherapy(IMRT).Methods:We reviewed the medical data of 251 patients with non-metastatic,NO-category NPC treated with IMRT.Receiver operating characteristic curves were used to calculate the cut-off value of the ENLN diameter for the prediction of disease failure.The biological equivalent dose(BED) for ENLNs was calculated.Patient survival was compared between the small and large ENLN groups.Independent prognostic factors were identified using the Cox proportional hazards model.Results:The estimated 4-year regional relapse-free survival rate was higher in patients with ENLNs ≥5.5 mm than in those with ENLNs <5.5 mm(100%vs.98.8%,P=0.049),whereas disease-free,overall,and distant metastasis-free survival rates were similar between the two groups.After adjusting for various factors,ENLN diameter was not identified as an independent prognostic factor(P > 0.05 for all survival rates).In the subgroup analysis,patients receiving BED ≥72 Gy had a similar prognosis as patients receiving BED <72 Gy in both the small and large ENLN groups.The multivariate analysis also confirmed that BED≥72 Gy was not associated with significantly improved prognosis in patients with NO-category NPC.Conclusions:A BED of 72 Gy to ENLNs is considerably sufficient to provide a clinical benefit to patients with NO-category NPC.Prospective studies are warranted to validate the findings in the present study.
基金supported by grants from the Science and Technology Project of Guangzhou City,China(No.14570006)the Planned Science and Technology Project of Guangdong Province,China(No.2013B020400004)
文摘Background: Little is known about the nature of metaistasis to small cervical lymph nodes(SCLNS) in the patients with nasopharyngeal carcinoma(NPC)examined by using 18-fluoro-2-deoxy-glucose(^(18)F-FDG) positron emission tomography/computed tomography(PET/CT).The present study aimed to evaluate the diagnostic values of PET/CT in identifying metastasis in SCLNs in NPC patients.Methods: Magnetic resonance images(MRI) and PET/CT scans for 470 patients with newly diagnosed, non-distant metastatic NPC were analyzed. Metastatic rates of SCLNs were defined by the positive number of SCLNs on PET/CT scans and total number of SCLNs on MRI scans. Receiver operating characteristic curve was applied to compare PET/CT-determined stage with MRI-determined stage.Results: In total, 2082 SCLNs were identified, with 808(38.8%) ≥ 5 and < 6 mm in diameter(group A), 526(25.3%)≥ 6 and < 7 mm in diameter(group B),374(18.0%)≥ 7 and < 8 mm in diameter(group C), 237(11.4%) ≥8 and<9 mm in diameter(group D),and 137(6.5%) ≥ 9 and <10 mm in diameter(group E).The overall metastatic rates examined by using PET/CT for groups A, B,C,D, and E were 3.5%, 8.0%, 31.3%, 60.0%, and 83.9%, respectively(P< 0.001). In level IV/Vb, the metastatic rate for nodes ≥ 8 mm was 84.6%. PET/CT examination resulted in modification of N category and overall stage for 135(28.7%) and 46(9.8%) patients, respectively. The areas under curve of MRIdetermined and PET/CT-determined overall stage were 0.659 and 0.704 for predicting overall survival, 0.661 and 0.711 for predicting distant metastasis-free survival, and 0.636 and 0.663 for predicting disease-free survival.Conclusions: PET/CT was more effective than MRI in identifying metastatic SCLNs, and the radiologic diagnostic criteria for metastatic lymph nodes in level IV/Vb should be re-defined.
文摘Objective: The purpose of this study was to investigate the impact of intensity modulated radiotherapy (IMRT) on surface doses for brain, abdomen and pelvis deep located tumors treated with 6 MV photon and to evaluate the skin dose calculation accuracy of the XIO 4.04 treatment planning system. Methods: More investigations for the influences of IMRT on skin doses would increase its applications for many treatment sites. Measuring skin doses in real treatment situations would reduce the uncertainty of skin dose prediction. In this work a pediatric human phantom was covered by a layer of 1 mm bolus at three treatment sites and thermoluminescent dosimeter (TLD) chips were inserted into the bolus at each treatment site before CT scan. Two different treatment plans [three-dimensional conformal radiation therapy (3DCRT) and IMRT] for each treatment sites were performed on XIO 4.04 treatment planning system using superposition algorism. Results: The results showed that the surface doses for 3DCRT were higher than the surface doses in IMRT by 1.6%, 2.5% and 3.2% for brain, abdomen and pelvis sites respectively. There was good agreement between measured and calculated surface doses, where the calculated surface dose was 15.5% for brain tumor calculated with 3DCRT whereas the measured surface dose was 12.1%. For abdomen site the calculated surface dose for IMRT treatment plan was 16.5% whereas the measured surface dose was 12.6%. Conclusion: The skin dose in IMRT for deep seated tumors is lower than that in 3DCRT which is another advantage for the IMRT. The TLD readings showed that the difference between the calculated and measured point dose is negligible. The superposition calculation algorism of the XIO 4.04 treatment planning system modeled the superficial dose well.
文摘Objective:This study was to compare 5 field conformal technique to the intensity modulated radiotherapy (IMRT) 8 fields technique in boosting locally advanced cancer cervix cases after external beam radiotherapy with respect to target volume coverage and dose to normal tissues. Methods:We conducted a single institutional comparative dosimetric analysis of 10 patients with cancer cervix who was presented to radiotherapy department in National Cancer Institute, Cairo in period between June 2012 to September 2012 and received a CRT boost in the place of planned brachytherapy after large field pelvic radiotherapy (PRT) with concurrent chemotherapy were retrospectively identified. All tumors were situated in the low central pelvis. Two plans were done for every patient; one using the 8 fields IMRT and the second one using 5 fields' 3DCRT the two techniques were then compared using dose volume histogram (DVH) analysis for the PTV, bladder, rectum and both femoral heads. Results:Comparing different DVHs, it was found that the planning target volume (PTV) was adequately covered in both plans while it was demonstrates that the 8 fields IMRT technique carried less doses reaching OARs (rectum, bladder, both femoral heads). Conclusion:From the present study, it is concluded that IMRT technique spared more efficiently OARs than CRT technique but both techniques covered the PTV adequately so whenever possible IMRT technique should be used.
基金Supported by a grant from Health Bureau of Lianyungang City’s Fund Program (No. 05051).
文摘Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty patients with middle and advanced stage NSCLC were randomized into two groups. Forty patients were underwent sequential therapy and other 40 patients were underwent concurrent therapy. IMRT was used in radiotherapy and NP regimen of vinorelbine+cispatin (NP) was used in chemotherapy. Results: (1) The overall response (CR+PR) rate was 75% in concurrent group and 45% in sequential group (P<0.05); (2) The treatment courses were 84 days and 140 days for concurrent group and sequential group respectively (P<0.05); (3) One-year survival rate in concurrent group was 72.4% and 52.3% in sequential group respectively; (4) The toxic effects can be tolerable by all of patients. Conclusion: The concurrent chemo-radiotherapy has better overall re- sponse, one-year survival rate and shorter treatment course than the sequential chemo-radiotherapy, so it is a better method for the treatment of middle and advanced stage NSCLC, but the long term survival rate will be studied.
文摘Objective： To evaluate if the combination of both prone position on a belly board and intensity-modulated radiotherapy （IMRT） further reduces the radiation dose to small bowel in pelvic RT for gynecologic malignancies. Methods： Conformal pelvic RT plans were computed in 13 patients with gynecologic malignancies who had pre-existing planning computed tomography （CT） scans in both the supine position and prone position on a belly board. There were 10 cervical cancer and 3 endometrial cancer patients. A limited arc technique （180° arc length） and an extended arc technique （340° arc length） were used in IMRT plans. Normal tissue regions of interest （ROI） included small bowel, large bowel and bladder. Dose and volume for normal tissue structures were traced and compared between supine and prone plans using the paired t-test. Results： For the limited arc technique, prone position using a belly board device improved small bowel sparing. Analysis of the results showed a 12~26 Gy reduction of volume of small bowel irradiation compared to the supine position. With the extended arc technique, there was no obvious radiation reduction in the prone position. Large bowel and bladder dose showed no significant differences between prone and supine position with either technique. Conclusion： Prone positioning on a belly board decreases the small bowel dose in gynecologic pelvic IMRT, and the magnitude of improvement depended on the limited arc IMRT technique used.
文摘Surgical excision and postoperative radiotherapy are widely accepted therapeutic modalities for sinonasal teratocarcinosarcoma （SNTCS）. Previous studies have shown that intensity-modulated radiation therapy （IMRT） is safe and effective for the treatment of some sinonasal malignancies. We hypothesize that use of IMRT for SNTCS may result in clinical benefits. We report here two cases of SNTCS that were treated by IMRT. One patient was given extensive IMRT involving elective neck irradiation. Follow-up examinations revealed no recurrence and metastasis 3.5 years after IMRT. Another patient simultaneously suffered from multiple systematical diseases and was administered involved-field radiotherapy. He was found to have a marginal recurrence during the follow up and eventually died 8 months after disease diagnosis. It was suggested in this study that appropriate use of IMRT for the treatment of SNTCS may achieve excellent local control.
文摘Objective: Juvenile Nasopharyngeal Angiofibroma (JNA) is a benign neoplasm with a high vascularity component, greater craniofacial involvement in adolescent patients, and aggressive local behaviour. In unresectable patients, radiotherapy is a therapeutic option for local control. Our aim in this study was to analyze the clinical benefit and local control provided by two modalities of radiotherapy: the Three-Dimensional Conformal (3DC) technique and volumetric modulated arc therapy (VMAT), applied to pediatric patients with JNA considered unresectable and non-recurrent. Methods: In retrospective study, the information was recorded from pediatric patients with a diagnosis of non-recurrent and unresectable JNA treated with radiotherapy at the Oncology Hospital of the National Medical Center SXXI of Mexico City, from March 2010 to March 2021. Radiotherapy management and its association with clinical outcomes of tumour control, and symptoms were assessed. In addition, an evaluation of acute and chronic toxicity was performed. Results: It was found that the median age was 14 years. 9 patients (37.5%) underwent 3DC and 15 (62.5%) VMAT. In terms of local control, and progression-free survival, we did not find significant difference between radiotherapy modalities (p ≤ 0.57). Acute toxicity for both modalities presented statistical differences for radio epithelitis (p = 0.03). Only Grade I and II radiation-induced acute toxicity was observed. Regarding chronic toxicity, statistical significance was observed for craniofacial hypoplasia, in relation to its absence in the VMAT group (p = 0.001). Conclusion: The VMAT presents improvements in dosimetry parameters that improve patient toxicity. In both techniques adequate tumour control was observed, however, the rarity of the disease is a limitation to establish the most appropriate therapeutic technique.
基金Supported by The National Natural Science Foundation of China, No. 30870738
文摘AIM： To compare the volumetric-modulated arc ther- apy （VMAT） plans with conventional sliding window intensity-modulated radiotherapy （c-IMRT） plans in esophageal cancer （EC）. METHODS： Twenty patients with EC were selected, including 5 cases located in the cervical, the upper, the middle and the lower thorax, respectively. Five plans were generated with the eclipse planning sys- tem： three using c-IMRT with 5 fields （5F）, 7 fields （7F） and 9 fields （gF）, and two using VMAT with a single arc （1A） and double arcs （2A）. The treatment plans were designed to deliver a dose of 60 Gy to the plan-ning target volume （PTV） with the same constrains in a 2.0 Gy daily fraction, 5 d a week. Plans were normal- ized to 95% of the PTV that received 100% of the pre- scribed dose. We examined the dose-volume histogram parameters of PTV and the organs at risk （OAR） such as lungs, spinal cord and heart. Monitor units （MU） and normal tissue complication probability （NTCP） of OAR were also reported. RESULTS： Both c-IMRT and VMAT plans resulted in abundant dose coverage of PTV for EC of different Io- cations. The dose conformity to PTV was improved as the number of field in c-IMRT or rotating arc in VMAT was increased. The doses to PTV and OAR in VMAT plans were not statistically different in comparison with c-IMRT plans, with the following exceptions： in cervical and upper thoracic EC, the conformity index （CI） was higher in VMAT （1A 0.78 and 2A 0.8） than in c-IMRT （5F 0.62, 7F 0.66 and 9F 0.73） and homogeneity was slightly better in c-IMRT （7F 1.09 and 9F 1.07） than in VMAT （1A 1,1 and 2A 1.09）, Lung V30 was lower in VMAT （1A 12.52 and 2A 12.29） than in c-IMRT （7F 14.35 and 9F 14.81）. The humeral head doses were significantly increased in VMAT as against c-IMRT. In the middle and lower thoracic EC, CI in VMAT （1A 0.76 and 2A 0.74） was higher than in c-IMRT （5F 0.63 Gy and 7F 0.67 Gy）, and homogeneity was almost similar between VMAT and c-IMRT. V20 （2A 21.49 Gy vs 7F 24.59 Gy and 9F 24.16 Gy） and V30 （2A 9.73 Gy vs 5F 12.61 Gy, 7F 11.5 Gy and 9F 11.37 Gy） of lungs in VMAT were lower than in c-IMRT, but low doses to lungs （V5 and Vl0） were increased. V30 （1A 48.12 Gy vs 5F 59.2 Gy, 7F 58.59 Gy and 9F 57.2 Gy）, V40 and V50 of heart in VMAT was lower than in c-IMRT. MUs in VMAT plans were significantly reduced in comparison with c-IMRT, maximum doses to the spinal cord and mean doses of lungs were similar between the two techniques. NTCP of spinal cord was 0 for all cases. NTCP of lungs and heart in VMAT were lower than in c-IMRT. The advantage of VMAT plan was enhanced by doubling the arc. CONCLUSION： Compared with c-IMRT, VMAT, especial- ly the 2A, slightly improves the OAR dose sparing, such as lungs and heart, and reduces NTCP and MU with a better PTV coverage.
文摘AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT and 42 VMAT).Dose were 63.8 Gy(HT)and 63.2 Gy(VMAT)in the tumour bed,52.2 Gy in the breast,50.4 Gy in supraclavicular nodes(SCN)and internal mammary chain(IMC)with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions.Margins to particle tracking velocimetry were greater in the VMAT cohort(7 mm vs 5 mm).RESULTS For the HT cohort,the coverage of clinical target volumes was as follows:Tumour bed:99.4%±2.4%;breast:98.4%±4.3%;SCN:99.5%±1.2%;IMC:96.5%±13.9%.For the VMAT cohort,the coverage was as follows:Tumour bed:99.7%±0.5%,breast:99.3%±0.7%;SCN:99.6%±1.4%;IMC:99.3%±3%.For ipsilateral lung,Dmean and V20 were 13.6±1.2 Gy,21.1%±5%(HT)and 13.6±1.4 Gy,20.1%±3.2%(VMAT).Dmean and V30 of the heart were 7.4±1.4 Gy,1%±1%(HT)and 10.3±4.2 Gy,2.5%±3.9%(VMAT).For controlateral breast Dmean was 3.6±0.2 Gy(HT)and 4.6±0.9 Gy(VMAT).Acute skin toxicity grade 3 was 5%in the two cohorts.CONCLUSION HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance.A longer follow-up is needed to assess the impact of low doses to healthy tissues.
文摘Objective: A dosimetric study was performed to evaluate the performance of volumetric modulated arc radiotherapy with RapidArc on locally advanced nasopharyngeal carcinoma (NPC). Methods: The CT scan data sets of 20 patients of locally advanced NPC were selected randomly. The plans were managed using volumetric modulated arc with RapidArc and fixed nine-field coplanar dynamic intensity-modulated radiotherapy (IMRT) for these patients. The dosimetry of the planning target volumes (PTV), the organs at risk (OARs) and the healthy tissue were evaluated. The dose prescription was set to 70 Gy to the primary tumor and 60 Gy to the clinical target volumes (CTV) in 33 fractions. Each fraction applied daily, five fractions per week. The monitor unit (MU) values and the delivery time were scored to evaluate the expected treatment efficiency. Results: Both techniques had reached clinical treatment’s requirement. The mean dose (Dmean), maximum dose (Dmax) and minimum dose (Dmin) in RapidArc and fixed field IMRT for PTV were 68.4±0.6 Gy, 74.8±0.9 Gy and 56.8±1.1 Gy; and 67.6±0.6 Gy, 73.8±0.4 Gy and 57.5±0.6 Gy (P<0.05), respectively. Homogeneity index was 78.85±1.29 in RapidArc and 80.34±0.54 (P<0.05) in IMRT. The conformity index (CI: 95%) was 0.78±0.01 for both techniques (P>0.05). Compared to IMRT, RapidArc allowed a reduction of Dmean to the brain stem, mandible and optic nerves of 14.1% (P<0.05), 5.6% (P<0.05) and 12.2% (P<0.05), respectively. For the healthy tissue and the whole absorbed dose, Dmean of RapidArc was reduced by 3.6% (P<0.05), and 3.7% (P<0.05), respectively. The Dmean to the parotids, the spinal cord and the lens had no statistical difference among them. The mean MU values of RapidArc and IMRT were 550 and 1,379. The mean treatment time of RapidArc and IMRT was 165 s and 447 s. Compared to IMRT, the delivery time and the MU values of RapidArc were reduced by 63% and 60%, respectively. Conclusion: For locally advanced NPC, both RapidArc and IMRT reached the clinic requirement. The target volume coverage was similar for the different techniques. The RapidArc technique showed some improvements in OARs and other tissue sparing while using reduced MUs and delivery time.
基金Supported by a grant from the Science and Technology Program Project Funds of Qianjiang(No.2014046)
文摘Objective This study evaluated the dosimetric consequences of selective partial salivary gland sparing during intensity-modulated radiotherapy(IMRT) for patients with nasopharyngeal carcinoma(NPC).Methods Ten patients with NPC were enrolled in the study.Two IMRT plans were produced for each patient:conventional(control) and partial salivary glands-sparing(treatment),with dose constraints to the entire parotid glands or partial salivary glands(including the parotid and submandibular glands,delineated with the adjacent distance of at least 0.5 cm between the glands and PTV,the planning target volume) in planning,respectively.Dosimetric parameters were compared between the two plans,including the V_(110%),V_(100%),V_(95%)(the volume covered by more than 110%,100%,or 95% of the prescribed dose),Dmin(the minimum dose) of PTV,homogeneity index(HI),conformity index(CI),and the mean dose and percentage of the volume receiving 30 Gy or more(V_(30)) for the parotid glands and submandibular glands.Results Treatment plans had significantly lower mean doses and V_(30) to both the entire parotid glands and partial parotid glands than those in control plans.The mean doses to the partial submandibular glands were also significantly lower in treatment plans than in control plans.The PTV coverage was comparable between the two plans,as indicated by V_(100%),V_(95%),Dmin,CI,and HI.The doses to critical structures,including brainstem and spinal cord,were slightly but not significantly higher in treatment plans than in control plans.Conclusion A selective partial salivary gland-sparing approach reduces the doses to parotid and submandibular glands during IMRT,which may decrease the risk of post-radiation xerostomia while not compromising target dose coverage in patients with NPC.
