Hospital volume and late survival after cancer surgery

Context: Although hospital procedure volume is clearly related to operative mortality with many cancer procedures, its effect on late survival is not well characterized. Objective: To examine relationships between hospital volume and late survival after different types of cancer resections. Design: 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. Study Participants: U.S. Medicare patients residing in SEER regions. Main Outcome Measures: 5-year survival. Results: 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. Conclusions: 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.