Department of Radiation Oncology, TUM School of Medicine and Health, TUM University Hospital, Klinikum rechts der Isar, Munich, Germany.
Department of Radiology, TUM School of Medicine and Health, TUM University Hospital, Klinikum rechts der Isar, Munich, Germany.
Breast. 2024 Dec;78:103819. doi: 10.1016/j.breast.2024.103819. Epub 2024 Oct 5.
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.
随机研究表明，与 5 周方案相比，（超）低分割在乳腺癌术后放疗中的肿瘤学等效性。由于二次恶性肿瘤的发病率低且潜伏期长，目前尚无关于分割方案对二次恶性肿瘤发展影响的可靠临床数据。
对于 20 名右侧或左侧乳腺癌患者，使用 3D-CRT（n=10）或 VMAT（n=10）为三种不同的分割方案创建术后治疗计划：5 周方案，50.4Gy 分 1.8Gy（28fx）；低分割，40.05Gy 分 2.67Gy（15fx）；超分割，26Gy 分 5.2Gy（5fx）。使用剂量依赖性剂量反应模型计算肺、对侧乳房、食管、肝脏、甲状腺、脊髓、骨骼和软组织的二次恶性肿瘤的 EARs（每 10000 患者年的绝对附加病例数）。
基于风险调节，（超）低分割显著降低了肺癌（LC）、对侧乳腺癌（CBC）和软组织肉瘤（STS）的 EAR（p<0.001）。对于超分割剂量概念，LC、CBC 和 STS 的中位 EAR 比常规分割低 42.8%、39.4%和 58.1%，比低分割低 31.2%、25.7%和 20.3%。与 VMAT 相比，3D-CRT 对 LC 和 CBC 二次恶性肿瘤风险的分割影响较小。然而，对于 STS，3D-CRT 对分割的影响大于 VMAT。
基于这项模拟研究，与 5 周方案相比，（超）低分割术后乳腺癌放疗可能与较低的二次恶性肿瘤风险相关。
