Breast cancer survival according to number of nodes removed.

BACKGROUND: Results from randomized trials indicate a 5.4% survival advantage associated with axillary dissection. To gain insight on survival outcomes when less than an axillary dissection is performed, we performed a retrospective analysis to determine survival outcome for node-negative and node-positive breast cancer patients when a variable number of nodes were excised.
METHODS: The data analyzed in this paper are from the Surveillance, Epidemiology, and End Results (SEER) database, from which 72,102 patients were selected whose breast cancer had been diagnosed in 1988 or later and who were aged 40-79 years at diagnosis, had a single primary lesion, and had 0 to 3 positive lymph nodes. Cases were separated into age groups (40 to 49 and 50 to 79 years), and node-negative cases were separated from those with one to three positive nodes.
RESULTS: This analysis indicates that even when all regional lymph nodes are pathologically negative, the number of nodes removed is associated with survival. In the group of breast cancer patients who had one to three pathologically positive nodes, as with the node-negative group, the higher the number of nodes removed, the greater the survival. The hazard rate for death in the node-negative group was roughly 5% less for each additional five nodes removed. For the node-positive group, the hazard rate for death was between 8% and 9% less for each additional five nodes removed.
CONCLUSIONS: This retrospective study supports the notion that removal of regional nodes, even when such nodes are interpreted as pathologically negative, is important for the long-term survival of breast cancer patients.