Variation in colectomy rates for benign polyp and colorectal cancer

Removal of pre-cancerous polyps on screening colonoscopy is a mainstay of colorectal cancer (CRC) prevention. Complex polyps may require surgical removal with colectomy, an operation with a 17% morbidity and 1.5% mortality rate. Recently, advanced endoscopic techniques have allowed some patients with complex polyps to avoid the morbidity of colectomy. However, the rate of colectomy for benign polyp in the United States is unclear, and variation in this rate across geographic regions has not been studied. We compared regional variation in colectomy rates for CRC versus benign polyp.

We performed a retrospective population-based study of Medicare beneficiaries undergoing colectomy for CRC or benign polyp, using the 100% Medicare Provider Analysis and Review files from 2010 to 2015. We used multivariable linear regression to obtain population-based colectomy rates for CRC and benign polyp at the hospital referral region (HRR) level, adjusted for age, sex, and race.

Of 280,815 patients, 157,802 (65.8%) underwent colectomy for CRC compared to 81,937 (34.2%) for benign polyp. Across HRRs, colectomy rates varied 5.8-fold for cancer (0.32-1.84 per 1000 beneficiaries). However, there was a 69-fold variation for benign polyp (0.01-0.69). While the rate of colectomy for CRC was correlated with the rate of colectomy for benign polyp (slope = 0.61, 95% CI 0.48-0.75), HRRs with the lowest or highest rates of colectomy for CRC did not necessarily have similarly low or high rates for benign polyp.

The use of colectomy for benign polyp is much more variable compared to CRC, suggesting overuse of colectomy for benign polyp in some regions. This variation may stem from provider-level differences, such as endoscopists' referral practice or skill or surgeons' decision to perform colectomy, or from limited access to advanced endoscopists. Interventions to increase endoscopic resection of benign polyps may spare some patients the morbidity and cost of surgery.