Quesada Stanislas, Fenoglietto Pascal, Gourgou Sophie, Lemanski Claire, Draghici Roxana, Ailleres Norbert, Prunaretty Jessica, Azria David, Bourgier Céline
Faculty of Medicine, University of Montpellier, Montpellier, France.
Department of Radiation Oncology, Montpellier Cancer Institute (ICM), Montpellier, France.
Front Oncol. 2022 Aug 18;12:967479. doi: 10.3389/fonc.2022.967479. eCollection 2022.
Volumetric Modulated Arc Therapy (VMAT) exhibits potent advantages regarding target volume coverage and protection of organs at risk, notably in the context of anatomical constraints. Nevertheless, reports concerning VMAT for the treatment of synchronous bilateral breast cancers (SBBC) have been scarce to date. As such, we conducted this observational study to assess efficacy, safety and feasibility of VMAT in SBBC.
From August 2011 to December 2017, 54 consecutive patients with SBBC with or without axillary nodes involvement underwent a treatment protocol containing radiotherapy using VMAT. A total dose (TD) of 52.2Gy in 29 fractions was delivered to breast and internal mammary chain (IMC) nodes Planning Target Volume (PTV) plus, if applicable, a TD of 49.3Gy in 29 fractions to the supra- and infra-clavicular nodes PTV and a TD of 63.22Gy in 29 fractions to tumor boost PTV. Lungs, heart, esophagus, trachea, liver, thyroid and spinal cord were considered as organs at risk. VMAT feasibility and organ at risk sparing were evaluated by treatments planning of the 20 first enrolled patients. Tolerance and patients' outcome were prospectively monitored by acute/late toxicities records and by the analysis of overall survival (OS), locoregional recurrence-free survival (LRFS) and recurrence-free survival (RFS).
Breast, supraclavicular nodes and boost PTV coverage was adequate with at least 98% of PTV encompassed by more than 95% of the prescribed dose. Less than 90% of IMC PTV was encompassed by 95% of the prescribed dose. Mean lung dose was 12.3Gy (range: 7.7 - 18.7); mean heart dose was 10.7Gy (range: 6.2 - 22.3). Concerning acute toxicities, only 2 patients experienced grade 3 skin toxicity (3.7%) and only 1 patient developed grade 1 pneumonitis. After a median follow-up of 5.3 years, grade 2 fibrosis and/or shrinking was observed in 5 patients (10%), and grade 3 fibrosis in 1 patients (2%). The 5-year LRFS-rate, RFS-rate and OS were 98% [95% CI= 86.12-99.70%], 96% [95% CI= 84.63-98.96%] and 100%, respectively.
容积调强弧形放疗（VMAT）在靶区覆盖及危及器官保护方面具有显著优势，尤其是在存在解剖学限制的情况下。然而，迄今为止，关于VMAT治疗同步双侧乳腺癌（SBBC）的报道较少。因此，我们开展了这项观察性研究，以评估VMAT治疗SBBC的疗效、安全性和可行性。
2011年8月至2017年12月，54例连续的SBBC患者，无论是否伴有腋窝淋巴结受累，均接受了包含VMAT放疗的治疗方案。乳腺和内乳链（IMC）淋巴结计划靶区（PTV）接受29次分割、总剂量（TD）为52.2Gy的照射；若适用，锁骨上和锁骨下淋巴结PTV接受29次分割、TD为49.3Gy的照射，肿瘤增敏PTV接受29次分割、TD为63.22Gy的照射。肺、心脏、食管、气管、肝脏、甲状腺和脊髓被视为危及器官。通过对最初入组的20例患者进行治疗计划评估VMAT的可行性和对危及器官的保护情况。通过急性/晚期毒性记录以及总生存（OS）、局部区域无复发生存（LRFS）和无复发生存（RFS）分析，前瞻性监测耐受性和患者预后。
乳腺、锁骨上淋巴结和增敏PTV的覆盖良好，至少98%的PTV被超过95%的处方剂量所覆盖。95%的处方剂量覆盖的IMC PTV不到90%。平均肺剂量为12.3Gy（范围：7.7 - 18.7）；平均心脏剂量为10.7Gy（范围：6.2 - 22.3）。关于急性毒性，仅2例患者出现3级皮肤毒性（3.7%），仅1例患者发生1级肺炎。中位随访5.3年后，5例患者（10%）出现2级纤维化和/或萎缩，1例患者（2%）出现3级纤维化。5年LRFS率、RFS率和OS分别为98% [95% CI = 86.12 - 99.70%]、96% [95% CI = 84.63 - 98.96%]和100%。
