Department of Radiation Oncology, Winship Cancer Institute, Emory University, Atlanta, GA.
Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA.
Clin Breast Cancer. 2022 Feb;22(2):127-135. doi: 10.1016/j.clbc.2021.06.003. Epub 2021 Jun 12.
Neoadjuvant chemotherapy (NAC) is increasingly used for operable breast cancer (BC). Appropriate radiation therapy (RT) fields (ie, whole breast [WB] ± regional nodal irradiation [RNI]) in patients who were clinically node positive (cN1) but convert to pathologically node negative (ypN0) after NAC are unknown and the subject of the accruing NSABP B-51 trial. We sought to compare outcomes between WB RT with or without RNI following breast conservation and sentinel lymph node biopsy (SLNB) alone in cN1, ypN0 women following NAC.
We identified all BC patients with cN1, ypN0 who underwent NAC followed by lumpectomy and SLNB between 2006 and 2015 in the National Cancer Database. RNI utilization was evaluated using Cochran-Armitage test. Overall survival between WB RT alone versus WB + RNI was compared using Kaplan-Meier with and without propensity score-based weighted adjustment and multivariable (MVA) Cox proportional hazards.
From 2006 to 2015, RNI use increased from 48.13% to 62.13% (Pfor trend <.001). The 10-year survival for WB alone versus WB + RNI was 83.6% and 79.5%, respectively (P= .14). On MVA analysis, the addition of RNI compared to WB alone was not associated with a survival benefit (WB vs. WB + RNI: hazard ratio 0.80, 95% confidence interval, 0.58-1.11, P= .19). Results were unchanged after propensity score-based adjustment.
For women with cN1 BC who convert to ypN0 following NAC and breast conserving surgery with SLNB alone, more extensive RNI may not provide a long-term survival benefit. Prospective validation via the NSABP B-51 trial will be essential.
新辅助化疗（NAC）越来越多地用于可手术乳腺癌（BC）。在接受 NAC 后临床淋巴结阳性（cN1）但病理淋巴结阴性（ypN0）的患者中，适当的放疗（RT）野（即全乳[WB]±区域淋巴结照射[RNI]）尚不清楚，这也是正在进行的 NSABP B-51 试验的主题。我们旨在比较 NAC 后行保乳手术和前哨淋巴结活检（SLNB）的 cN1、ypN0 女性中，接受 WB RT 加或不加 RNI 后的结果。
我们在国家癌症数据库中确定了所有在 2006 年至 2015 年间接受 NAC 后行保乳手术和 SLNB 的 cN1、ypN0 BC 患者。使用 Cochran-Armitage 检验评估 RNI 的使用情况。Kaplan-Meier 法和基于倾向评分加权调整的 Kaplan-Meier 法以及多变量（MVA）Cox 比例风险模型比较 WB RT 单药治疗与 WB+RNI 的总生存率。
2006 年至 2015 年，RNI 的使用率从 48.13%增加到 62.13%（P趋势<.001）。WB 单药治疗与 WB+RNI 的 10 年生存率分别为 83.6%和 79.5%（P=.14）。在 MVA 分析中，与 WB 单药治疗相比，加用 RNI 并不能带来生存获益（WB 与 WB+RNI：风险比 0.80，95%置信区间，0.58-1.11，P=.19）。在基于倾向评分的调整后，结果保持不变。
对于接受 NAC 后行保乳手术和 SLNB 的 cN1 BC 且转化为 ypN0 的女性，更广泛的 RNI 可能不会带来长期生存获益。通过 NSABP B-51 试验进行前瞻性验证将是至关重要的。
