Aim: The simultaneous irradiation of target volumes of different total dose levels using intensity modulated radiotherapy leads to reduced doses per fraction and longer treatment times in target volumes of 2nd?to 4th?...Aim: The simultaneous irradiation of target volumes of different total dose levels using intensity modulated radiotherapy leads to reduced doses per fraction and longer treatment times in target volumes of 2nd?to 4th?order. Does the thereby caused reduced biological effectiveness induce an increased recurrence risk? The current work deals with the problem of recurrences of patients with head and neck carcinomas treated either with an intensitiy (IMRT) or with a volumetric modulated (VMAT) irradiation technique. Methods: From October 2002 to September 2014, 699 patients with carcinomas of the head and neck were irradiated using IMRT or VMAT. The median follow up of the patients was 21.9 months (2 to 145 months). Primary tumor regions (1st?order target volume) of 565 patients were treated with doses per fraction of 2 Gy. Accordingly, further 133 target volumes of the primary tumor received reduced doses per fraction. In 1 patient, the lymphatic drainage was treated solely without irradiation of the primary region. For the lympatic drainage, 854 1st?order target volumes were treated with a dose per fraction of 2 Gy. Reduced doses per fraction were applied to further 1780 target volumes. Results: 54 of 699 patients developed a recurrence in the primary tumor region after radio-(chemo) therapy, 4 patients developed a recurrence of the primary tumor and a unilateral recurrence of the lymphatic drainage, 2 patients a recurrence of the primary tumor and a bilateral lymph node recurrence. 18 patients showed an isolated unilateral recurrence and additionally 2 patients a bilateral recurrence of the lymphatic drainage. 619 patients stayed recurrence free. In primary tumor regions, receiving a dose per fraction of 2 Gy 55 patients (9.7%) developed a recurrence, whereas in target volumes receiving a reduced dose per fraction 5 patients (3.8%) developed a recurrence (p < 0.001). In lympatic drainage target volumes receiving a dose per fraction of 2 Gy, 25 target volumes (2.9%) developed a recurrence, whereas in target volumes receiving a reduced dose per fraction, 5 patients (0.3%) developed a recurrence (p = 0.001). Conclusion: The recurrence risk in target volumes of 2nd?to 4th?order was not increased due to reduced doses per fraction deposited by means of a simultaneous integrated boost technique. Therefore, the simultaneous irradiation of target volumes with different dose levels is safely applicable within one treatment plan.展开更多
文摘Aim: The simultaneous irradiation of target volumes of different total dose levels using intensity modulated radiotherapy leads to reduced doses per fraction and longer treatment times in target volumes of 2nd?to 4th?order. Does the thereby caused reduced biological effectiveness induce an increased recurrence risk? The current work deals with the problem of recurrences of patients with head and neck carcinomas treated either with an intensitiy (IMRT) or with a volumetric modulated (VMAT) irradiation technique. Methods: From October 2002 to September 2014, 699 patients with carcinomas of the head and neck were irradiated using IMRT or VMAT. The median follow up of the patients was 21.9 months (2 to 145 months). Primary tumor regions (1st?order target volume) of 565 patients were treated with doses per fraction of 2 Gy. Accordingly, further 133 target volumes of the primary tumor received reduced doses per fraction. In 1 patient, the lymphatic drainage was treated solely without irradiation of the primary region. For the lympatic drainage, 854 1st?order target volumes were treated with a dose per fraction of 2 Gy. Reduced doses per fraction were applied to further 1780 target volumes. Results: 54 of 699 patients developed a recurrence in the primary tumor region after radio-(chemo) therapy, 4 patients developed a recurrence of the primary tumor and a unilateral recurrence of the lymphatic drainage, 2 patients a recurrence of the primary tumor and a bilateral lymph node recurrence. 18 patients showed an isolated unilateral recurrence and additionally 2 patients a bilateral recurrence of the lymphatic drainage. 619 patients stayed recurrence free. In primary tumor regions, receiving a dose per fraction of 2 Gy 55 patients (9.7%) developed a recurrence, whereas in target volumes receiving a reduced dose per fraction 5 patients (3.8%) developed a recurrence (p < 0.001). In lympatic drainage target volumes receiving a dose per fraction of 2 Gy, 25 target volumes (2.9%) developed a recurrence, whereas in target volumes receiving a reduced dose per fraction, 5 patients (0.3%) developed a recurrence (p = 0.001). Conclusion: The recurrence risk in target volumes of 2nd?to 4th?order was not increased due to reduced doses per fraction deposited by means of a simultaneous integrated boost technique. Therefore, the simultaneous irradiation of target volumes with different dose levels is safely applicable within one treatment plan.
