Disease-free survival and prognostic significance of metastatic lymph node ratio in T1-T2 N positive breast cancer patients. A population registry-based study in a European country.

Background: The ratio of positive lymph nodes between the total number of harvested lymph nodes (metastatic lymph node ratio, MLNR) has been proposed as an alternative to the total number of lymph nodes alone in predicting outcomes for patients with breast cancer. Because there can be differences between European and non-European populations, the authors present the first study analyzing MLNR influence over disease-free survival (DFS) by using a population-based cancer registry in a European country.

Methods: Data from 441 patients with T1-2 N1-3 breast cancer included in the Castellon Cancer Registry (Comunidad Valenciana, Spain) were used. Cumulative DFS was determined using the Kaplan-Meier method, with univariate comparisons between groups through the log-rank test. The Cox proportional hazards model was used for multivariate analysis.

Results: At univariate analysis, factors influencing the 10-year DFS rate were tumor size, conservative or nonconservative surgery, histologic grade, histologic type, radiotherapy, tamoxifen, estrogen and progesterone receptor status, p53 status, total number of positive lymph nodes, and MLNR. At multivariate analysis, tumor size, MLNR, and progesterone receptor status were revealed to be independent prognostic factors; the metastatic lymph node ratio was the most notably independent factor (hazard ratio 1.02, 5.21, and 0.61, respectively).

Conclusions: MLNR is a stronger prognostic factor for recurrence than the total number of positive lymph nodes in T1-T2 N1-3 breast cancer.