Rate of nonendoscopic surgeries for nonmalignant colorectal polyps significantly increased from 5.9 to 9.4 per 100,000 people from 2000 to 2014, according to a study in Gastroenterology.

These surgeries are not only associated with a much higher risk to patients than endoscopic procedures, but they are significantly less cost effective, confusing investigators as to the cause of the increase.

“The literature to date is clear that endoscopic resection is the preferred management of nonmalignant colorectal polyps,” Anne Peery, MD, gastroenterologist at the University of North Carolina at Chapel Hill, and colleagues explained. “Among patients who have surgery for a nonmalignant colorectal polyp, 14% will have at least one major short-term postoperative event.”

Data from 1,230,458 surgeries conducted during 2000-2014 and recorded in the Healthcare Cost and Utilization Project National Inpatients Sample were included in this study. Patients who underwent a nonendoscopic procedure for nonmalignant polyps were predominantly non-Hispanic white, covered by Medicare, from the highest household income range, and an average age of 66 years.

While non-Hispanic white patients had the highest overall rate increase by ethnicity, rising from 5.6 to 10.5 per 100,000 population, rates in non-Hispanic black and Hispanic patients also rose significantly, increasing from 3.5 to 5.8 per 100,000 population, and from 1.1 to 3.7 per 100,000 population, respectively.

Regionally, rates of surgery were higher in the Midwest (10.8 per 100,000) and the South (10.6 per 100,000) than in the Northeast (7.8 per 100,000) and West (7.5 per 100,000). Incidence rates rose equally during the study period for both men and women.

Large urban teaching hospitals were found to have the largest rate increase when data were stratified by teaching status, a finding which caught Dr. Peery and fellow investigators by surprise.

“We had hypothesized that surgery for nonmalignant colorectal polyps would be both uncommon and declining in teaching hospitals where providers are more likely to be familiar with current guidelines and to have access to endoscopic mucosal resection,” wrote the investigators. “Instead, we found that surgery for nonmalignant colorectal polyps is both common and significantly increasing in teaching hospitals.”

The investigators first hypothesized the increased rate in teaching hospitals could be due to a higher concentration of case referrals to these high-volume centers, following a trend of centralizing cancer procedures. However, there has been no other sign that colon and rectal cancer procedures are following this trend.

Another option considered by Dr. Peery and her colleagues was that increased procedures may stem from a rise in colorectal cancer screening; however, the data indicate screenings did not change from 2010 to 2015, leaving investigators with few final guesses to go on.

“It is also conceivable that increasing production pressure and inadequate reimbursement for endoscopic mucosal resection may persuade endoscopists to refer patients with complex nonmalignant colorectal polyps for surgery,” said Dr. Peery and fellow investigators. “Finally, there is the issue of risk … for endoscopists without additional training in advanced endoscopic resection, these risks may be perceived as too great, especially when they have the option of referring for a surgical resection.”

There is a possibility that the incidence of surgery was over- or underestimated, as investigators were using ICD-9 codes to identify cases, and patients with diverticulitis were also excluded, which may have affected results.

The investigators reported no relevant financial disclosures.

SOURCE: Peery A et al. Gastroenterology. 2018 Jan 6. doi: 10.1053/j.gastro.2018.01.003 .