Hospital volume and late survival after cancer surgery

Although hospital procedure volume is clearly related to operative mortality with many cancer procedures, its effect on late survival is not well characterized.

To examine relationships between hospital volume and late survival after different types of cancer resections.

Using the national Surveillance Epidemiology and End Results (SEER)-Medicare linked database (1992-2002), we identified all patients undergoing major resections for lung, esophageal, gastric, pancreatic, colon, and bladder cancer (n = 64,047). Relationships between hospital volume and survival were assessed using Cox proportional hazards models, adjusting for patient characteristics and use of adjuvant radiation and chemotherapy.

U.S. Medicare patients residing in SEER regions.

5-year survival.

Although there were statistically significant relationships between hospital volume and 5-year survival with all 6 cancer types, the relative importance of volume varied markedly. Absolute differences in 5-year survival probabilities rates between low-volume hospitals (LVHs) and high-volume hospitals (HVHs) ranged from 17% for esophageal cancer resection (17% vs. 34%, respectively) to only 3% for colon cancer resection (45% vs. 48%). Absolute differences in 5-year survival between LVHs and HVHs fell between these ranges for lung (6%), gastric (6%), pancreatic (5%), and bladder cancer (4%). Volume-related differences in late survival could not be attributed to differences in rates of adjuvant therapy.

Along with lower operative mortality, HVHs have better late survival rates with selected cancer resections than their lower-volume counterparts. Mechanisms underlying their better outcomes and thus opportunities for improvement remain to be identified.