Purpose: To evaluate the clinical outcomes and relationship between tumor size, lymph node status, and prognosis in a large cohort of patients with confirmed triple receptor-negative breast cancer (TNBC).
Patients and methods: We reviewed 1,711 patients with TNBC diagnosed between 1980 and 2009. Patients were categorized by tumor size and nodal status. Kaplan-Meier product limit method was used to calculate overall survival (OS) and relapse-free survival (RFS). A Sidak adjustment was used for multiple group comparisons. Cox proportional hazards models were fit to determine the association of tumor size and nodal status with survival outcomes after adjustment for other patient and disease characteristics.
Results: Median age was 48 years (range, 21 to 87 years). At a median follow-up of 53 months (range, 0.7 to 317 months), there were 614 deaths and 747 recurrences. The 5-year OS was 80% for node-negative patients (N0), 65% for one to three positive lymph nodes (N1), 48% for four to nine positive lymph nodes (N2), and 44% for ≥ 10 positive lymph nodes (N3; P < .0001). The 5-year RFS rates were 67% for N0, 52% for N1, 36% for N2, and 33% for N3 (P < .0001). Pairwise comparison by nodal status showed that when comparing N0 with node-positive disease, there was a significant difference in OS and RFS (P < .001 all comparisons). However, when comparing N1 with N2 and N3 disease regardless of tumor size, there were no significant differences in OS or RFS.
Conclusion: In patients with TNBC, once there is evidence of lymph node metastasis, the prognosis may not be affected by the number of positive lymph nodes.