Chest Wall and Supraclavicular/Infraclavicular Nodal Region are Common Sites of Locoregional Recurrence for Women with Breast Cancer after Mastectomy Irrespective of TN Stage or Molecular Subtypes

Abstract

To analyze the failure patterns of locoregional recurrence (LRR) and identify the prognostic factors for local recurrence (LR) and regional recurrence (RR) in breast cancer patients after mastectomy. Between 1999 and 2014, 7207 women with breast cancer after mastectomy and axillary dissection were analyzed. All didn’t receive postmastectomy radiotherapy (PMRT). 4671 (64.8%) had pT1-2N0 disease (low-risk), 2078 (28.8%) had pT1-2N1 disease (intermediate-risk) and 458 (6.4%) were defined as high-risk, which included 360 with pT3-4 or pN2-3 disease and 98 pT1-2N1 after neoadjuvant chemotherapy. Among the 5427 patients who had sufficient information to construct molecular subtype, there were 2451 (45.2%) luminal A, 579 (10.7%) luminal B-Her2 negative, 814 (15.0%) luminal B-Her2 positive, 593 (10.9%) Her2 enriched, and 990 (18.2%) triple negative (TN). The distribution of accumulated LRR was analyzed. The LR and RR rates were estimated by the Kaplan-Meier method, and the differences were compared with Log-rank test. Multivariate analysis was performed using Cox logistic regression analysis. With a median follow-up of 62.9 months (6.0-194.6), 481 patients had LRR, including chest wall in 225 (46.8%), supraclavicular/infraclavicular nodes (SCN) in 242 (50.3%), axilla in 96 (20.0%) and internal mammary nodes (IMN) in 52 (10.8%) patients. For LRR patients with low, intermediate and high risk group, 93 (54.1%), 83 (44.9%), 69 (55.6%) had chest wall recurrence, 68 (39.5%), 110 (59.5%), 64 (51.6%) had SCN recurrence, 27 (15.7%), 37 (20.0%), 32 (25.8%) had axilla recurrence, and 28 (16.3%), 20 (10.8%), 4 (3.2%) had IMN recurrence. For LRR patients with luminal A, luminal B-Her2 negative, luminal B-Her2 positive, Her2-enriched, and TN tumors, 48 (45.3%), 23 (56.1%), 25 (43.1%), 25 (57.2%), 61 (58.1%) had chest wall recurrence, 51 (48.1%), 23 (56.1%), 32 (55.2%), 33 (62.3%), 51 (48.6%) had SCN recurrence, 21 (19.8%), 10 (24.4%), 13 (22.4%), 9 (17.0%), 22 (21.0%) had axilla recurrence, and 9 (8.5%), 7 (17.1%), 6 (10.3%), 7 (13.2%), 14 (13.3%) had IMN recurrence. The median interval to LR and RR was 51.6 and 29.2 months. In multivariate analysis, age (≤45 years vs. >45 years), tumor location (inner quadrant vs. other quadrants), T stage (T3-4 vs. T1-2), N stage (pN3 vs. pN2 vs. pN1 vs. pN0), hormone receptor status (negative vs. positive) were significant prognostic factors for both LR and RR (p < 0.05). In breast cancer after mastectomy without PMRT, both chest wall and supraclavicular/infraclavicular nodal region are common sites of LRR, irrespective of TN stage or molecular subtypes. The prognostic factors for LR and RR are similar, which indicates that chest wall and supraclavicular/infraclavicular nodal irradiation should be considered in all patients who planned to receive PMRT.