Impact of Number of Positive Lymph Nodes and Lymph Node Ratio on Survival of Women with Node-Positive Breast Cancer.

Abstract

This study aimed to evaluate the association of axillary lymph node ratio (LNR) and number of positive lymph nodes (pN) with the risk of breast cancer recurrence and death. A retrospective cohort study of node-positive stage II and III breast cancer patients diagnosed and treated between 2008 and 2009 at the Brazilian National Cancer Institute (INCA), Brazil. Overall and disease-free survival curves for number of positive lymph nodes (pN) and lymph node ratio (LNR) risk groups were constructed using the Kaplan-Meier method and compared by the log-rank test. Multivariate analysis was performed using stepwise forward Cox regression models. In total, 628 women with node-positive breast cancer were included. Most patients (69.5%) had advanced clinical stage tumors (≥IIB). The median follow-up was 58 months (range: 3-92 months). The adjusted recurrence hazard of pN2 and pN3 patients was 2.47 (95% Confidence Interval [CI] 1.72-3.56) and 2.42 (1.62-3.60), respectively, compared to pN1 patients (p<0.001), while the hazard of intermediate (0.21-0.65) and high-risk (>0.65) LNR was 2.11 (1.49-3.00) and 3.19 (2.12-4.80), respectively, compared to low-risk LNR (≤0.20) patients (p<0.001). On the other hand, the hazard of death of pN2 and pN3 patients was 2.17 (1.42-3.30) and 2.41 (1.53-3.78), respectively (p<0.001), and the hazard of intermediate (0.21-0.65) and high-risk (>0.65) LNR patients was 1.70 (1.13-2.56) and 2.74 (1.75-4.28), respectively (p≤0.001). Higher pN and LNR were associated with shorter disease-free survival and overall survival times.