Failure patterns of locoregional recurrence in women with T1-2N1 breast cancer after modified radical mastectomy

Objective To analyze the failure patterns of locoregional recurrence (LRR) and investigate the range of radiotherapy in T1-2N1 breast cancer patients undergoing modified radical mastectomy. Methods From September 1997 to April 2015, 2472 women with T1-2N1 breast cancer after modified radical mastectomy without neoadjuvant systemic therapy were treated in our hospital. 1898 patients who did not undergo adjuvant radiotherapy were included in this study. The distribution of accumulated LRR was analyzed. The LR and RR rates were estimated by the Kaplan-Meier method, and the prognostic factors were identified in univariate analyses with Log-rank test. Multivariate analysis was performed using Cox logistic regression analysis. Results With a median follow-up of 71.3 months (range 1.1-194.6), 164 patients had LRR, including supraclavicular/infraclavicular lymph nodes in 106(65%), chest wall in 69(42%), axilla in 39(24%) and internal mammary lymph nodes (IMNs) in 19 patients (12%). In multivariate analysis, age (>45 years vs.≤45 years), tumor location (other quadrants vs. inner quadrant), T stage (T1vs. T2), the number of positive axillary lymph nodes (1 vs. 2-3), hormone receptor status (positive vs. negative) were significant prognostic factors for both LR and RR. Conclusions In patients with T1-2N1 breast cancer after modified radical mastectomy, the most common LRR site is supraclavicular/infraclavicular nodal region, followed by chest wall. The axillary or IMN recurrence is rare. The prognostic factors for LR and RR are similar, which indicates that supraclavicular/infraclavicular and chest wall irradiation should be considered for postmastectomy radiotherapy. Key words: Breast neoplasm/modified radical mastectomy; Positive lymph node; Locoregional recurrence patterns