Favorable prognosis in patients with T1a/T1bN0 triple-negative breast cancers treated with multimodality therapy

Abstract

Background: The authors evaluated the clinical characteristics, natural history, and outcomes of patients who had ≤1 cm, lymph node-negative, triple-negative breast cancer (TNBC).

Methods: After excluding patients who had received neoadjuvant therapy, 1022 patients with TNBC who underwent definitive breast surgery during 1999 to 2006 were identified from an institutional database. In total, 194 who had lymph node-negative tumors that measured ≤1 cm comprised the study population. Clinical data were abstracted, and survival outcomes were analyzed.

Results: The median follow-up was 73 months (range, 5-143 months). The median age at diagnosis was 55.5 years (range, 27-84 years). Tumor (T) classification was microscopic (T1mic) in 16 patients (8.2%), T1a in 49 patients (25.3%), and T1b in 129 patients (66.5%). Most tumors were poorly differentiated (n = 142; 73%), lacked lymphovascular invasion (n = 170; 87.6%), and were detected by screening (n = 134; 69%). In total, 129 patients (66.5%) underwent breast-conserving surgery, and 65 patients (33.5%) underwent mastectomy. One hundred thirteen patients (58%) received adjuvant chemotherapy, and 123 patients (63%) received whole-breast radiation. The patients who received chemotherapy had more adverse clinical and disease features (younger age, T1b tumor, poor tumor grade; all P < .05). Results from testing for the breast cancer (BRCA) susceptibility gene were available for 49 women: 19 women had BRCA1 mutations, 7 women had BRCA2 mutations, and 23 women had no mutations. For the entire group, the 5-year local recurrence-free survival rate was 95%, and the 5-year distant metastasis-free survival rate was 95%. There was no difference between patients with T1mic/T1a tumors and patients with T1b tumors in the distant recurrence rate (94.5% vs 95.5%, respectively; P = .81) or in the receipt of chemotherapy (95.9% vs 94.5%, respectively; P = .63).

Conclusions: Excellent 5-year locoregional and distant control rates were achievable in patients with TNBC who had tumors ≤1.0 cm, 58% of whom received chemotherapy. These results identified a group of patients with TNBC who had favorable outcomes after early detection and multimodality treatment.