Hospital Universitari Son Espases, Radiation Oncology Department, Carretera de Valldemossa, 79, 07020, Palma de Mallorca (Islas Baleares), Spain.
Institut d´Investigació Sanitaria Illes Balears, IdISBA, Palma de Mallorca, Spain.
Clin Transl Oncol. 2021 Sep;23(9):1915-1922. doi: 10.1007/s12094-021-02600-1. Epub 2021 Apr 8.
Synchronous bilateral breast cancer (SBBC) accounts for 1-3.5% of breast cancer patients. The aim of this study was to evaluate dosimetric issues, clinical outcomes, and acute toxicities for SBBC patients receiving synchronous bilateral hypofractionated radiotherapy (SBHRT) and to compare them with patients treated with synchronous bilateral normofractionated RT schedule (SBNRT).
From April 2016 to March 2020, 39 SBBC patients were referred to our institution. Patients were divided according to their prescription dose: Group A: 50 Gy/25fx (fractions), B: 60-64 Gy/25fx, C: 40.05 Gy/15fx; D: 48 Gy/15fx. Toxicity was evaluated using Common Terminology Criteria for Adverse Events (CTCAE)v.5.0.
34 patients were finally evaluated. Median follow-up was 24 months for NF schedule and 9 months for HF schedule. In the HF schedule, no acute side-effects > G2 were observed and no dermatitis was reported in 6 month´s assessments. 95% of patients have no evidence of disease and only 1 patient presented local relapse in the first mammography after RT. No distant failures or deaths were observed. Regarding dosimetric issues, the inter-patient average D for the heart was: Group A: 5.0 Gy (4.6-5.5), Group B: 4.4 Gy (4.1-5.4), Group C: 4.8 Gy (4.5-5.1) and Group D: 5.3 Gy (4.4-5.6). For the lungs, the inter-patient average D was: Group A: 10.8 Gy (9.8-12.2), Group B: 11.5 Gy (11.3-12), Group C: 9.8 Gy (9.3-10.5) and Group D: 10.5 Gy (10-11.3).
This is the first study reporting the safety, feasibility, and tolerability of 40.05 Gy/15fx over 3 weeks for the treatment of SBBC patients. Further study with larger accrual is mandatory.
双侧同步乳腺癌（SBBC）占乳腺癌患者的 1-3.5%。本研究旨在评估双侧同步低分割放疗（SBHRT）治疗 SBBC 患者的剂量学问题、临床结果和急性毒性，并与接受双侧同步常规分割放疗（SBNRT）的患者进行比较。
自 2016 年 4 月至 2020 年 3 月，39 例 SBBC 患者被转诊至我院。患者根据处方剂量分为：A 组：50Gy/25fx；B 组：60-64Gy/25fx；C 组：40.05Gy/15fx；D 组：48Gy/15fx。毒性采用常见不良事件术语标准（CTCAE）v.5.0 进行评估。
34 例患者最终纳入分析。常规分割组的中位随访时间为 24 个月，高分割组为 9 个月。在高分割组中，未观察到 > G2 级的急性不良反应，6 个月评估时无皮肤炎报告。95%的患者无疾病证据，仅 1 例患者在放疗后首次乳房 X 光检查时出现局部复发。未观察到远处失败或死亡。在剂量学方面，心脏的患者间平均 D 值为：A 组：5.0Gy（4.6-5.5）；B 组：4.4Gy（4.1-5.4）；C 组：4.8Gy（4.5-5.1）；D 组：5.3Gy（4.4-5.6）。对于肺部，患者间平均 D 值为：A 组：10.8Gy（9.8-12.2）；B 组：11.5Gy（11.3-12）；C 组：9.8Gy（9.3-10.5）；D 组：10.5Gy（10-11.3）。
这是首例报道 40.05Gy/15fx 治疗 SBBC 患者的安全性、可行性和耐受性的研究。需要更大样本量的进一步研究。
