Influence of Surgeon Volume on the Survival from Stage III Colon Cancer Open Access

Malone, Mackenzie (2015)

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Background: Surgeon volume has been found to be associated with improved survival for colon cancer patients undergoing curative colon resection as part of treatment. The aim of this study is to further explore this relationship among patients with late stage colon cancer.

Methods: We conducted a retrospective population-based cohort study utilizing linked Surveillance, Epidemiology, and End Results (SEER)- Medicare database. We identified 15,009 patients aged 65 years and older diagnosed with a primary diagnosis of stage III colon cancer in a SEER area and treated with colon resection between 2000 and 2009. Surgeons were identified using individual surgeon identification numbers. Average surgeon volume was based on the number of colon resection claims submitted over the 10-year study period and the years where at least one colon resection was performed. Outcome measures were 30 day overall mortality and 5-year cause specific mortality. Kaplan-Meier survival curves were used to estimate survival probabilities. Cox-proportional hazard models were used to estimate adjusted hazard ratios.

Results: A total of 3,999 individual surgeons were identified as primary surgeons of cohort members. A statistically significant improvement in survival was observed as the volume of operating surgeon increased (P < .0001). In the adjusted analysis there was an observed statistically significant decrease in risk of either mortality outcome associated with increased surgeon volume (P < .0001 for both 30-day and 5-year mortality). The observed inverse association was stronger in the short-term survival analysis when compared to the long-term survival analysis.

Conclusions: The annual average surgeon volume of the primary treating surgeon may predict mortality outcomes following a colon resection for patients with stage III colon cancer. Therefore, improvement in colon cancer care should focus on quality of operating surgeon. Further research is needed to explore the optimal surgeon volume required to observe the most benefit in survival outcomes.

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Public Health Significance...18


Tables and Figures...30

Appendix A: Exploratory Analysis Tables...35

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