Survival of Lymph Node-Negative Breast Cancer Patients in Relation to Number of Lymph Nodes Examined

Abstract

Objective To assess the relationship between number of lymph nodes examined and survival of patients diagnosed with node-negative localized breast cancer using a large sample of patients from population-based cancer registries in the United States. Summary Background Data Conflicting results have been reported from studies on the relationship between number of lymph nodes examined and survival of patients diagnosed with node-negative localized breast cancer. Methods The study included 69,543 patients diagnosed in 1988–97 with localized invasive node-negative breast cancer reported to nine population-based registries in the U.S. National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) Program of population-based cancer registries. Hazard ratios for groups defined by number of nodes examined were analyzed in Cox proportional hazards regression models that included age, tumor size and grade, race/ethnicity, and other variables. Results A significantly higher risk of death from breast cancer was found among patients with 0, 1 to 3, or 4 to 10 nodes examined than with 20-plus nodes examined, even among patients with tumors 2 cm or smaller. Conclusions Future studies of survival of node-negative patients, by number of nodes examined, should include information on comorbidity and treatment.