Effect of the number of uninvolved nodes on survival in early breast cancer.

A high number of uninvolved axillary nodes was found by some authors to be associated with poor survival in node-negative breast cancer. We searched for confirmation and extend the investigation to node-positive cases, using population data from the SEER Program. Patients selected were women aged 40-69 years, diagnosed 1988-1997, T1-T2 breast cancer, undergoing axillary dissection with 4-35 nodes examined. Survivals were estimated by the product-limit method and were computed on pooled data. Results in node-negative patients (n=37,519) showed a 5-year overall survival from 92% (95% confidence interval: 88-95%) with 4 uninvolved nodes, to 93% (87-98%) with 34 uninvolved nodes. In node-positive patients (n=16,978), the 5-year survival increased from 50% (44-56%) with 0 uninvolved nodes, to 91% (82-100%) with 30 uninvolved nodes. Survival graphs indicated an improvement or a plateau with higher number of uninvolved nodes. The graphs also suggested that the ratio of involved and uninvolved nodes might be correlated with survival. We conclude that there was no evidence of poor outcome associated with a high number of uninvolved nodes. The incidental finding that ratio-based characterization of node involvement might be a prognostic factor will be further investigated.