随机研究证明了乳腺癌术后放疗中（超）大分割与 5 周方案的肿瘤学等效性。由于继发性恶性肿瘤发生率低、潜伏期长，目前尚无可靠的临床数据说明分次治疗方案对继发性恶性肿瘤发生发展的影响。针对20例右侧或左侧乳腺癌患者，采用以下方法制定术后治疗方案： 3D-CRT (n = 10) 或 VMAT (n = 10) 适用于三种不同的分割方案：1.8Gy (28fx) 中 50.4Gy 的 5 周方案、2.67Gy (15fx) 中 40.05Gy 的大分割以及 2.67Gy (15fx) 中的超大分割5.2Gy (5fx) 中为 26Gy。使用分数依赖性剂量反应模型计算肺部、对侧乳房、食道、肝脏、甲状腺、脊髓、骨骼和软组织继发性恶性肿瘤的 EAR（每 10,000 名患者年的绝对额外病例数）。在风险调节方面，（超）大分割导致肺癌 (LC)、对侧乳腺癌 (CBC) 和软组织肉瘤 (STS) 的 EAR 显着降低 (p < .001)。对于超大分割剂量概念，LC、CBC 和 STS 的中位 EAR 比传统分割低 42.8%、39.4% 和 58.1%，比大分割低 31.2%、25.7% 和 20.3%。与 VMAT 相比，3D-CRT 中分割对 LC 和 CBC 继发恶性肿瘤风险的影响不太明显。然而，对于 STS，3D-CRT 分割的影响比 VMAT 更大。根据这项模拟研究，与 5 周计划相比，（超）大分割术后乳腺癌放疗可能与较低的继发性恶性肿瘤风险相关.版权所有 © 2024。由 Elsevier Ltd 出版。

Randomized studies demonstrated the oncological equivalence of (ultra-)hypofractionation compared to a 5-week schedule in postoperative radiotherapy of breast cancer. Due to the low incidence and long latency of secondary malignancies, there are currently no reliable clinical data regarding the influence of fractionation regimens on the development of secondary malignancies.For 20 patients with right or left-sided breast cancer, postoperative treatment plans were created using 3D-CRT (n = 10) or VMAT (n = 10) for three different fractionation schedules: 5-week schedule with 50.4Gy in 1.8Gy (28fx), hypofractionation with 40.05Gy in 2.67Gy (15fx) and ultra-hypofractionation with 26Gy in 5.2Gy (5fx). The EARs (absolute additional cases of disease per 10,000 patient-years) for secondary malignancies in the lung, contralateral breast, esophagus, liver, thyroid, spinal cord, bones and soft tissue were calculated using a fraction-dependent dose-response model.Based on risk modulation, (ultra-)hypofractionation resulted in significantly lower EARs for lung cancer (LC), contralateral breast cancer (CBC) and soft tissue sarcoma (STS) (p < .001). For the ultra-hypofractionated dose concept the median EARs for LC, CBC and STS were 42.8 %, 39.4 % and 58.1 % lower compared to conventional fractionation and 31.2 %, 25.7 % and 20.3 % compared to hypofractionation. The influence of fractionation on the risk of secondary malignancies for LC and CBC was less pronounced with 3D-CRT than with VMAT. For STS, however, the influence of fractionation was greater with 3D-CRT than with VMAT.Based on this simulation study (ultra-)hypofractionated postoperative breast cancer irradiation may be associated with a lower risk of secondary malignancies compared to a 5-week schedule.Copyright © 2024. Published by Elsevier Ltd.