ImportancePostmastectomy radiation therapy (PMRT) improves local-regional disease control and patient survival. Hypofractionation (HF) regimens have comparable efficacy and complication rates with improved quality of life compared with conventional fractionation (CF) schedules. However, the use of HF after mastectomy in patients undergoing breast reconstruction has not been prospectively examined.ObjectiveTo compare HF and CF PMRT outcomes after implant-based reconstruction.Design, Setting, and ParticipantsThis randomized clinical trial assessed patients 18 years or older undergoing mastectomy and immediate expander or implant reconstruction for breast cancer (Tis, TX, or T1-3) and unilateral PMRT from March 8, 2018, to November 3, 2021 (median [range] follow-up, 40.4 [15.4-63.0] months), at 16 US cancer centers or hospitals. Analyses were conducted between September and December 2023.InterventionsPatients were randomized 1:1 to HF or CF PMRT. Chest wall doses were 4256 cGy for 16 fractions for HF and 5000 cGy for 25 fractions for CF. Chest wall toxic effects were defined as a grade 3 or higher adverse event.Main Outcomes and MeasuresThe primary outcome was the change in physical well-being (PWB) domain of the Functional Assessment of Cancer Therapy–Breast (FACT-B) quality-of-life assessment tool at 6 months after starting PMRT, controlling for age. Secondary outcomes included toxic effects and cancer recurrence.ResultsOf 400 women (201 in the CF arm and 199 in the HF arm; median [range] age, 47 [23-79] years), 330 patients had PWB scores at baseline and at 6 months. There was no difference in the change in PWB between the study arms (estimate, 0.13; 95% CI, −0.86 to 1.11; P = .80), but there was a significant interaction between age group and study arm (P = .03 for interaction). Patients younger than 45 years had higher 6-month absolute PWB scores if treated with HF rather than CF regimens (23.6 [95% CI, 22.7-24.6] vs 22.0 [95% CI, 20.7-23.3]; P = .047) and reported being less bothered by adverse effects (mean [SD], 3.0 [0.9] in the HF arm and 2.6 [1.2] in the CF arm; P = .02) or nausea (mean [SD], 3.8 [0.4] in the HF arm and 3.6 [0.8] in the CF arm; P = .04). In the as-treated cohort, there were 23 distant (11 in the HF arm and 12 in the CF arm) and 2 local-regional (1 in the HF arm and 1 in the CF arm) recurrences. Chest wall toxic effects occurred in 39 patients (20 in the HF arm and 19 in the CF arm) at a median (IQR) of 7.2 (1.8-12.9) months. Fractionation was not associated with chest wall toxic effects on multivariate analysis (HF arm: hazard ratio, 1.02; 95% CI, 0.52-2.00; P = .95). Fewer patients undergoing HF vs CF regimens had a treatment break (5 [2.7%] vs 15 [7.7%]; P = .03) or required unpaid time off from work (17 [8.5%] vs 34 [16.9%]; P = .02).Conclusions and RelevanceIn this randomized clinical trial, the HF regimen did not significantly improve change in PWB compared with the CF regimen. These data add to the increasing experience with HF PMRT in patients with implant-based reconstruction.Trial RegistrationClinicalTrials.gov Identifier: NCT03422003

中文翻译：

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基于种植体的重建后大分割放疗与常规分割乳房切除术后放疗


重要性乳房切除术后放射治疗 （PMRT） 可改善局部区域疾病控制和患者生存率。与传统分割 （CF） 方案相比，大分割 （HF） 方案具有相当的疗效和并发症发生率，生活质量得到改善。然而，尚未对接受乳房重建的患者乳房切除术后 HF 的使用进行前瞻性检查。目的比较种植体重建术后 HF 和 CF PMRT 结局。设计、设置和参与者这项随机临床试验评估了 2018 年 3 月 8 日至 2021 年 11 月 3 日（中位 [范围] 随访，40.4 [15.4-63.0] 个月）在美国 16 个癌症中心或医院接受乳房切除术和即刻扩张器或植入物重建治疗乳腺癌（Tis、TX 或 T1-3）和单侧 PMRT 的患者。分析于 2023 年 9 月至 12 月期间进行。干预患者以 1：1 的比例随机分配到 HF 或 CF PMRT 组。HF 的胸壁剂量为 4256 cGy（16 次）和 5000 cGy（25 次）。胸壁毒性作用被定义为 3 级或更高级别的不良事件。主要结局和措施主要结局是开始 PMRT 后 6 个月癌症治疗功能评估-乳腺 （FACT-B） 生活质量评估工具的身体健康 （PWB） 领域的变化，控制年龄。次要结局包括毒性作用和癌症复发。结果在 400 名女性 （CF 组 201 名，HF 组 199 名;中位 [范围] 年龄，47 [23-79] 岁） 中，330 名患者在基线和 6 个月时有 PWB 评分。研究组之间 PWB 的变化没有差异（估计，0.13;95% CI，-0.86 至 1.11;P = .80），但年龄组和研究组之间存在显着的交互作用 （P = .03 表示交互）。如果接受 HF 而不是 CF 方案治疗，45 岁以下患者的 6 个月绝对 PWB 评分更高 （23.6 [95% CI，22.7-24.6] vs 22.0 [95% CI，20.7-23.3];P = .047），并报告较少受到不良反应的困扰 （平均值 [SD]，HF 组为 3.0 [0.9]，CF 组为 2.6 [1.2];P = .02） 或恶心 （平均值 [SD]，HF 组为 3.8 [0.4]，CF 组为 3.6 [0.8];P = .04）。在接受治疗的队列中，有 23 例远处复发 （HF 组 11 例，CF 组 12 例） 和 2 例局部区域 （HF 组 1 例，CF 组 1 例） 复发。39 例患者 （HF 组 20 例，CF 组 19 例） 发生胸壁毒性作用，中位 （IQR） 为 7.2 （1.8-12.9） 个月。分割与多变量分析中的胸壁毒性作用无关 （HF 组：风险比，1.02;95% CI，0.52-2.00;P = .95）。接受 HF 与 CF 方案的患者治疗中断较少 （5 [2.7%] vs 15 [7.7%];P = .03） 或需要无薪休假 （17 [8.5%] 对 34 [16.9%];P = .02）。结论和相关性在这项随机临床试验中，与 CF 方案相比，HF 方案没有显着改善 PWB 的变化。这些数据增加了基于种植体的重建患者对 HF PMRT 的日益增长的体验。试验注册临床试验。gov 标识符： NCT03422003