Hospital volume and operative mortality in cancer surgery: a national study.

BACKGROUND: Although initiatives to regionalize cancer surgery are already under way, the relative importance of volume in cancer surgery is disputed. HYPOTHESIS: We examined surgical mortality with 8 cancer resections in the US population to better quantify the influence of hospital volume.
METHODS: Using information from the all-payer Nationwide Inpatient Sample (1995-1997), we examined mortality with 8 cancer resections (N = 195 152). After dividing patients into 3 evenly sized volume groups based on hospital procedure volume (low, medium, and high), we used regression techniques to describe relationships between hospital volume and in-hospital mortality, adjusting for patient characteristics.
RESULTS: Trends toward lower operative risks at high-volume hospitals were observed for 7 of the 8 procedures. However, differences between low- and high high-volume hospitals were statistically significant for only 3 operations (esophagectomy, 15.0% vs 6.5%; pancreatic resection, 13.1% vs 2.5%; and pulmonary lobectomy, 10.1% vs 8.9%, respectively). Although they did not reach statistical significance, absolute differences in mortality between low- and high-volume hospitals were greater than 1% for the following 3 procedures: gastrectomy, 8.7% vs 6.9%; cystectomy, 3.6% vs 2.5%; and pneumonectomy, 10.6% vs 8.9%, respectively. Mortality reductions for nephrectomy and colectomy were small. In general, in terms of absolute differences in mortality, the effect of volume was greatest in elderly patients.
CONCLUSIONS: Operative mortality decreases with increasing hospital volume for several cancer resections. However, volume may be most important in patients who are older and at higher risk.