Lymph node ratio as prognostic after neoadjuvant therapy in breast cancer.

Abstract

123 Background: Lymph node ratio (LNR) is defined as the proportion of involved nodes over total number of nodes. The latter may be superior to TNM staging as a prognostic indicator in breast cancer treated surgically first. Pathological staging after neoadjuvant therapy (NAT) is based on the residual cancer burden (RCB) in breast and nodes. We hypothesized that LNR after NAT offers additional useful prognostic information. Methods: Patients receiving NAT were identified through the Stanford Tumor Registry. Based on previously published classifications LNRs in node positive disease was classified as low (L) 0.01-0.2, intermediate (I) 0.21-0.65, and high (H) > 0.65. Other discriminant cut-off points were sought. Kaplan-Meier log-rank test was used for survival analysis. Results: 105 node-negative and 92 node-positive cases were identified (2003 -2010). Median number of nodes examined was 13, range 2-40. LNR among the node-positive cohort varied from 0.03 to 1.0. The distribution of positive nodes for L was 1-4, for I 1-13, and for H 2-25. The 3-year DFS and OS were 94% and 98%, for node-negative cases, and 66% and 77% for node-positive cancers. Survival for L = 79% (median 55%); I = 56.2% (median 52%); and H = 55.6% (median 49%). Using 0.5 as a new discriminant, the 3 and 5-year OS for LNR < 0.5 was 78.1% and 69.9%, and for LNR > 0.5 was 52.2% and 39.8%, respectively (p = 0.02). Conclusions: LNR of 0.5 was found to discriminatefor survivalin patients after NAT. This differs from the LNR categories defined for patients who had surgery first. Further validation in larger dataset is warranted.