Xu Fei-Fei, Cao Lu, Xu Cheng, Cai Gang, Wang Shu-Bei, Qi Wei-Xiang, Chen Jia-Yi
Department of Radiation Oncology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Front Oncol. 2022 Feb 24;12:789198. doi: 10.3389/fonc.2022.789198. eCollection 2022.
The effect of adjuvant irradiation after mastectomy in early-stage breast cancer patients remains controversial. The present study aims to explore the clinical benefit obtained from adjuvant radiotherapy among post-mastectomy pT1-2N1 breast cancer patients who received adjuvant modern systemic therapy.
Medical records of consecutive patients with pT1-2N1 breast cancer who received mastectomy in our institution between January 2009 and December 2016 were retrospectively reviewed. High-risk features consist of patient age, number of positive lymph nodes, T stage, and Ki67 index, which were developed previously at our institution using early-stage breast cancer patients after mastectomy without adjuvant radiotherapy. Differences of survival and local recurrence were compared between no-postmastectomy radiotherapy (PMRT) and PMRT group according to number of risk factors. The time-to-event curves were calculated by the Kaplan-Meier methods and compared by the log-rank test. Propensity score matching (PSM) was performed to reduce the imbalances in patient characteristics.
A total of 548 patients were enrolled (no-PMRT: 259 and PMRT: 289). After a median follow-up of 69 months, the 5-year rate of DFS, BCSS, and LRR in the overall cohort was 90.2%, 97.4%, and 3.6%, respectively. PMRT did not significantly improve DFS, BCSS, and LRRFS in the whole cohort. Patients were divided into low-risk (with no or one risk factor) and high-risk (with two or more risk factors) groups. According to the univariable and multivariable analysis, high-risk group (HR = 1.81, 95% CI 1.11-2.98, = 0.02) was demonstrated as an independent risk factor for DFS. For the high-risk group, PMRT significantly improved DFS from 81.4% to 91.9% and BCSS from 95.5% to 98.6% and decreased the 5-year rate of LRR from 5.6% to 1.4%, respectively ( < 0.01, = 0.05, and = 0.06). However, no survival benefit from PMRT was observed in the low-risk group in terms of DFS, BCSS, and LRR ( = 0.45, = 0.51, and = 0.99, respectively). In multivariate analysis, PMRT remained an independent prognostic factor for DFS (HR = 0.50, 95% CI 0.24-1.00, = 0.05) in the high-risk group. After PSM analysis, the survival benefit of PMRT was sustained in high-risk patients.
PMRT significantly improved DFS in high-risk pT1-2N1 breast cancer patients, but not in low-risk patients. Independent validation of our scoring system is recommended.
早期乳腺癌患者乳房切除术后辅助放疗的效果仍存在争议。本研究旨在探讨接受辅助性现代全身治疗的乳房切除术后pT1-2N1乳腺癌患者从辅助放疗中获得的临床益处。
回顾性分析2009年1月至2016年12月在我院接受乳房切除术的连续pT1-2N1乳腺癌患者的病历。高危特征包括患者年龄、阳性淋巴结数目、T分期和Ki67指数，这些是我们机构之前利用乳房切除术后未接受辅助放疗的早期乳腺癌患者制定的。根据危险因素数量，比较无乳房切除术后放疗（PMRT）组和PMRT组之间的生存和局部复发差异。采用Kaplan-Meier方法计算事件发生时间曲线，并通过对数秩检验进行比较。进行倾向评分匹配（PSM）以减少患者特征的不平衡。
共纳入548例患者（无PMRT组：259例；PMRT组：289例）。中位随访69个月后，整个队列的5年无病生存率（DFS）、乳腺癌特异性生存率（BCSS）和局部复发率（LRR）分别为90.2%、97.4%和3.6%。PMRT在整个队列中未显著改善DFS、BCSS和LRRFS。患者分为低危（无或有一个危险因素）和高危（有两个或更多危险因素）组。根据单变量和多变量分析，高危组（HR = 1.81，95%CI 1.11-2.98，P = 0.02）被证明是DFS的独立危险因素。对于高危组，PMRT显著将DFS从81.4%提高到91.9%，将BCSS从95.5%提高到98.6%，并将5年LRR率从5.6%降低到1.4%（P < 0.01，P = 0.05，P = 0.06）。然而，在低危组中，就DFS、BCSS和LRR而言，未观察到PMRT有生存获益（分别为P = 0.45，P = 0.51，P = 0.99）。在多变量分析中，PMRT在高危组中仍然是DFS的独立预后因素（HR = 0.50，95%CI 0.24-1.00，P = 0.05）。经过PSM分析，PMRT对高危患者的生存获益得以维持。
PMRT显著改善了高危pT1-2N1乳腺癌患者的DFS，但对低危患者无效。建议对我们的评分系统进行独立验证。
