21基因复发评分（RS）用于预测雌激素受体（HR）阳性乳腺癌在1-3个阳性淋巴结的化疗效益。前瞻性-回顾性研究显示，在使用他莫昔芬治疗的患者中，RS对全身和区域复发有预测意义。我们的目标是评估RS是否可以用于预测放射治疗后的生存效益。使用国家癌症数据库（NCDB）识别了2010-2016年间进行乳房切除术和腋窝分期检查的HR+、HER2阴性、T1-3、N1、M0乳腺癌患者中年龄≤75岁且具有可用的RS的女性。采用Kaplan-Meier和Cox比例风险模型来确定治疗与总体生存（OS）之间的关联。采用单变量和多变量分析确定与PMRT和OS相关的变量。共鉴别出了8907名患者。其中，3203名患者（36%）接受了辅助性PMRT，5704名患者（64%）未接受。整个队列中，接受PMRT的患者5年OS为97.5%，未接受的患者为96.8%（P = 0.063）。在调整了所有协变量后，对于RS ≤ 25的患者，在辅助性PMRT的加入下，5年OS没有统计学意义的改善（97.5%对98.1%，P = 0.093）。此外，腋窝淋巴结清扫（P = 0.58）和化疗的加入（P = 0.312）也没有生存效益。在我们的一个有1-3个阳性淋巴结和RS ≤ 25的患者队列中，放射治疗后的省略对OS没有影响。我们的结果表明，RS可以用于个体化的PMRT决策。© 2023. Society of Surgical Oncology.

The 21-gene recurrence score (RS) is used to predict benefit from chemotherapy in hormone receptor (HR)-positive breast cancer with one to three positive lymph nodes. Prospective-retrospective studies have shown that the RS is prognostic for both systemic and locoregional recurrence in tamoxifen-treated patients. We aimed to assess whether RS could be utilized to predict a survival benefit from postmastectomy radiation therapy (PMRT).The National Cancer Database (NCDB) was used to identify women ≤ 75 years of age with HR+, HER2-negative, T1-3, N1, M0 breast cancer who underwent mastectomy and axillary staging with available RS during the years 2010-2016. Kaplan-Meier and Cox proportional hazards models were used to identify association between treatment and overall survival (OS). Univariate and multivariate analyses were used to identify variables correlating with PMRT and OS.A total of 8907 patients were identified. Of the total, 3203 (36%) patients received adjuvant PMRT and 5704 (64%) did not. Across the entire cohort, 5-year OS was 97.5% for patients receiving PMRT and 96.8% for those who did not (P = 0.063). After adjusting for all covariates, in patients with RS ≤ 25, there was no statistically significant improvement in 5-year OS with the addition of adjuvant PMRT (97.5% versus 98.1% P = 0.093). Moreover, no survival benefit was seen with axillary node dissection (P = 0.58) or with the addition of chemotherapy (P = 0.312).In our cohort of patients with one to three positive nodes and a RS ≤ 25, omission of post-mastectomy radiation therapy had no impact on OS. Our results suggest that RS may be utilized in the individualized decision making on PMRT.© 2023. Society of Surgical Oncology.