Deeper sedation with propofol may improve detection of serrated polyps during colonoscopy

Deeper sedation with propofol may improve detection of serrated polyps during colonoscopy

In patients undergoing colonoscopy to screen for colorectal cancer, deeper sedation with the anesthetic propofol may improve detection of “serrated” polyps. A type of precancerous lesion that can be difficult to detect, reports a study in the first online edition ofAnesthesiologythe peer-reviewed journal of the American Society of Anesthesiologists (ASA).

Our study provides the first evidence that monitored anesthesia treatment with propofol could improve the detection of serrated polyps, which are more often missed by colonoscopy than adenomatous polyps. “Propofol-based anesthesia may contribute to a more effective screening process for colorectal cancer, especially in patients with risk factors for serrated polyps.”

Aurora N. Quaye, MD, lead author, member of the Acute Pain and Regional Anesthesia Service at Maine Medical Center, Portland

Almost all colon cancers begin as small growths called polyps. Detecting and removing polyps during colonoscopy can prevent them from developing into cancer. Compared to a more common type of polyp called adenoma, serrated polyps may be harder to detect because they are often flatter and fit into the folds of colon tissue.

Propofol is an alternative to moderate sedation -; sometimes called “conscious” sedation –; for colonoscopy. “Propofol provides deeper sedation and also begins to work and wear off more quickly compared to conscious sedation,” explained Dr. Quaye. Research has shown that propofol-based anesthesia is more efficient and improves patient and provider satisfaction. The new study is the first to examine whether propofol might be associated with improved detection of serrated polyps.

The analysis included detailed information on more than 54,000 completed colonoscopies from the New Hampshire Colonoscopy Registry. The interventions were carried out between 2015 and 2020; all patients were older than 50 years. The frequency of polyp detection, including serrated polyps and adenomas, was compared in patients under moderate sedation with those under propofol-based anesthesia.

The overall polyp detection rate was higher when colonoscopy was performed with propofol: 34%, compared to 24.5% with moderate sedation. The results were similar when analyzing a "limited" sample of about 19,000 colonoscopies performed in facilities that did not predominantly use one form of sedation over another: the overall polyp detection rate was 30.3% with propofol versus 25.7% with moderate sedation.

After adjusting for other confounding factors in these 19,000 colonoscopies, propofol was still associated with a clinically and statistically significant 13% higher likelihood of detecting serrated polyps, although other types of polyps showed no difference in detection.

The conclusions are strengthened by the use of systematically collected clinical registry data, the researchers note. However, the study cannot provide information about how propofol might improve the detection of serrated polyps. “Propofol may increase patient comfort and relaxation and optimize the detection of polyps, which are more difficult to detect,” said Dr. Quaye. “In addition, propofol can cause relaxation of the smooth muscle in the colon, allowing for more careful examination and better visualization.”

The researchers emphasize the need for further studies to clarify the potential benefits of propofol for polyp detection. “The finding that propofol-based anesthesia could improve the detection of precancerous polyps could bring us closer to our goal of further optimizing the use of colonoscopy for the prevention and early detection of colorectal cancer,” said Dr. Quaye.

According to an accompanying editorial by Douglas A. Colquhoun, MB, ChB, MSc, MPH, University of Michigan, Ann Arbor, and colleagues, the modest but significant reported association between propofol use and serrated polyp detection highlights the “promise and danger” of studies using data from clinical registries. While the authors of the editorial caution that the results should be interpreted with caution due to limitations in analyzing registry data, they emphasize the importance of maintaining access to propofol and call for further, "rigorously conducted" studies that focus on the value of anesthesia care for patients undergoing colonoscopy.

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