Survival of lymph node-negative breast Cancer patients in relation to number of lymph nodes examined

This study examined the association between numbers of lymph nodes removed at diagnosis and survival in a large number of patients with node-negative breast cancer. Patients were identified from nine regional cancer registries in the United States National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) Program of population-based registries. A total of 69,543 women diagnosed from 1988 to 1997 with localized, invasive breast cancer of 5.0 cm or less with negative lymph nodes were identified. Over the years of the study, the trend was to remove fewer lymph nodes. More women had 20 or more nodes examined in the years 1988-1995 than in 1996-1997, and fewer women had 0-3 nodes examined in 1988-1995 than in 1996-1997 (P <. 001). The numbers of lymph nodes removed also decreased with advancing age. The proportion of women over 75 years of age who had more than 20 nodes removed was 12.1%, compared to 46.3% who had no nodes removed (P <.001). When a multivariate analysis of known risk factors for death from breast cancer was conducted using data from this sample, tumor grade and size were significant predictors. Women with breast tumors of 1-2 cm had more than double the risk of dying from disease than those whose tumors were 1 cm or less, and the risk doubled again for those with tumors of 3-4 cm. Similarly, the risk of death from breast cancer was more than twice as great for tumor grades 3 and 4 compared to grades 1 and 2. A greater risk was seen for younger women versus older women, black women compared to non-Hispanic white women, and unmarried versus married women. In women with primary tumors 2 cm or less in diameter who had negative nodes, the risk of death was greater for those patients who had no nodes, 1-3 nodes or 4-10 nodes removed compared to those in whom 20 or more nodes were examined (6.8% vs. 4.8% deaths, P <.001). There was no significant difference in survival between these women with 20 nodes or more sampled and those with 11-14 or 15-19 nodes removed.