Surgery following neoadjuvant chemotherapy (NAC) is increasingly utilized for breast cancer treatment with respect to downstage and recurrent risk reduction. However, there are some uncertainties about the solutions of adjuvant radiotherapy (design of RT field and indication in low-risk patients) in patients after NAC, especially in clinically node-positive patients. The objective of this study is to identify the risk factors of loco-regional recurrence (LRR), relapse and overall survival (OS)

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... egarding tumor response post-NAC in this institution. Methods: From 2007 to 2015, 90 patients with newly diagnosed clinical stage II (n=44) or III (n=46) breast cancer and pathological positive lymph nodes who received chemotherapy followed by breast conserving surgery or mastectomy, adjuvant radiotherapy, and some with adjuvant systemic therapy were identified. All of them received anthracycline-based or taxane-based chemotherapy, external beam radiotherapy and systemic treatment including target or hormone therapy if indicated. The patient characteristics included clinical T/N stage, pathologic T/N stage, response after NAC, tumor grade, surgical margin, the presence or absence of lymphovascular invasion and extracapsular extension, the total number of lymph nodes dissection, the positive lymph nodes ratio (pLNR), tumor biomarker status [estrogen receptor (ER)/progesterone receptor (PR)/human epidermal growth factor receptor 2 (HER-2)], and adjuvant chemotherapy/target therapy or not. Univariate and multivariate analyses for risks of locoregional recurrence (LRR), relapse (any local, regional or distant recurrence), and overall survival (OS) and the survival curves of LRR and relapse were performed.