Colorectal specialization and survival in colorectal cancer

It is recognized that higher surgeon volume is associated with improved survival in colorectal cancer. However, there is a paucity of national studies that have evaluated the relationship between surgical specialization and survival.

We used the Surveillance, Epidemiology, and End Results Medicare cancer registry to examine the association between colorectal specialization (CRS) and disease-specific survival (DSS) between 2001 and 2009. A total of 21,432 colon cancer and 5893 rectal cancer patients who underwent elective surgical resection between 2001 and 2009 were evaluated. Univariate and multivariate Cox survival analysis was used to identify the association between surgical specialization and cancer-specific survival.

Colorectal specialists performed 16.3% of the colon and 27% of the rectal resections. On univariate analysis, specialization was associated with improved survival in Stage II and Stage III colon cancer and Stage II rectal cancer. In multivariate analysis, however, CRS was associated with significantly improved DSS only in Stage II rectal cancer [hazard ratio (HR) 0.70, P = 0.03]. CRS was not significantly associated with DSS in either Stage I (colon HR 1.14, P = 0.39; rectal HR 0.1.26, P = 0.23) or Stage III (colon HR 1.06, P = 0.52; rectal HR 1.08, P = 0.55) disease. When analysis was limited to high volume surgeons only, the relationship between CRS and DSS was unchanged.

CRS is associated with improved DSS following resection of Stage II rectal cancer. A combination of factors may contribute to long-term survival in these patients, including appropriate surgical technique, multidisciplinary treatment decisions and guideline-adherent surveillance. CRS probably contributes positively to these factors resulting in improved survival.