Abstract
BACKGROUND: Despite advances in neoadjuvant systemic therapy (NST), some patients with aggressive T4 breast cancers do not respond. The efficacy of 'heroic' mastectomy in maintaining local control is unclear. METHODS: In consecutive patients with primary or recurrent T4 cancers with < 50% shrinkage on NST who underwent mastectomy from 2007 to 2017, clinicopathologic characteristics and locoregional recurrence (LRR) were examined. RESULTS: Among 104 patients, 59 (57%) had primary T4M0, 12 (12%) had locally recurrent T4M0, and 33 (32%) had T4M1 disease. Median age was 58.5 years and the majority had high-grade (74%) ductal cancers (85%); 45 (44%) were estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-), 26 (25%) were HER2 positive (HER2+), and 31 (30%) were triple negative (TN). Postoperative complications developed in 41 (39%) patients. At a median follow-up of 37 months, 42 (40%) patients developed LRR. TN (hazard ratio [HR] 7.5) and HER2+ (HR 2.67) subtypes, lymphovascular invasion (LVI; HR 3.80), and positive margins (HR 4.09) were predictive of LRR. The 3-year LRR rate was highest and overall survival (OS) was lowest among patients with TN cancers, at 66% (95% confidence interval [CI] 48-83%) and 30% (95% CI 14-47%), respectively. CONCLUSIONS: After heroic mastectomy, postoperative complications were frequent and LRR occurred in 40% of patients despite a median OS of 3.8 years. Among TN patients, the 3-year LRR rate of 66% and 3-year OS of 30% suggest limited surgery benefit. Careful patient selection is prudent when considering heroic mastectomy.