Effects of hospital volume on life expectancy after selected cancer operations in older adults: a decision analysis

Abstract

Background: In addition to lower operative mortality, patients undergoing selected cancer operations at high volume centers have improved longterm survival. We sought to determine the overall effect of hospital volume on life expectancy after cancer surgery.

Study design: We used a Markov decision analysis model to estimate life expectancy for patients undergoing resection for pancreatic, lung, or colon cancer. Model inputs included probabilities of operative mortality and longterm survival. For input data, we examined operative mortality (in-hospital or within 30 days) stratified by volume in over 400,000 patients undergoing resection for these three cancers using the national Medicare database (1994-1999). Risks of late mortality were abstracted from published studies (MEDLINE, 1966 to present) to model the effect of hospital volume on longterm survival. In analysis, we first calculated life expectancy for patients undergoing surgery at very low, low, medium, high, and very high volume hospitals. We then explored the effects of various regionalization strategies.

Results: Life expectancy increased steadily with hospital volume for all three cancers. Life expectancy after pancreatic cancer resection increased linearly with hospital volume: from 1.9 years at very low volume centers to 3.6 years at very high volume centers. For lung cancer, life expectancy ranged from 5.4 to 6.6 years. Increases in life expectancy for colon cancer were not as dramatic: from 6.8 at very low volume hospitals to 7.4 years at very high volume hospitals. Differences in life expectancy across volume strata were largely attributable to differences in longterm survival, not operative mortality. From a policy perspective, regionalizing surgery for colon cancer would produce the greatest overall life-expectancy gains, but it would require moving most patients.

Conclusions: Patients aged 65 and older with pancreatic, lung, and colon cancer have substantially greater life expectancy after cancer resection at higher volume hospitals. Further work is needed to understand the mechanisms underlying differences in performance across hospitals in cancer care.