In a recent publication in Clinical Gastroenterology and Hepatology, researchers conducted a cross-sectional study to approximate the incidence and odds of detecting colorectal cancer (CRC) and advanced colorectal neoplasia during colonoscopy in patients with diverticulitis compared with CRC screening.

The authors wrote, “Colonoscopy is often recommended following an episode of diverticulitis to exclude missed colorectal cancer (CRC). This is a controversial recommendation based on limited evidence.”

For this study, researchers gathered and reviewed data from the Gastrointestinal Quality Improvement Consortium registry involving patients who were aged ≥40 years and were undergoing outpatient colonoscopy for an indication of diverticulitis follow-up or CRC screening. The data were collected between January 2012 and December 2021 at 779 sites across the United States.

The study’s primary objective was to ascertain the prevalence of CRC and advanced colorectal neoplasia (ACN) on colonoscopy in outpatient. ACN includes lesions that might mirror the presentation of diverticulitis. Additionally, CRC symptoms can look comparable with diverticulitis, and misdiagnosis can delay the implementation of appropriate clinical intervention.

The researchers gathered and reviewed data for 4,591,921 outpatient colonoscopies performed for screening and 91,993 colonoscopies for diverticulitis follow-up. They found that the overall prevalence of CRC was 0.33% and 6.9% for ACN among patients undergoing colonoscopy for the average-risk cancer screening. They also discovered that the prevalence of CRC augmented with age for both screening colonoscopies and colonoscopies with a diverticulitis indication, and the overall prevalence of CRC for the diverticulitis patients was 0.31% and ACN 5.2%, demonstrating how less likely CRC occurs in this patient population.

The authors wrote, “Compared to screening, patients with diverticulitis were less likely to have CRC (adjusted OR [odds ratio] 0.84, 95% CI 0.74-0.94). CRC prevalence decreased to 0.17% in colonoscopies performed for diverticulitis only. Compared to screening, patients with diverticulitis as the only indication were less likely to have CRC (adjusted OR 0.49, 95% CI 0.36-0.68). CRC prevalence increased to 1.43% in patients with complicated diverticulitis. Compared to screening, patients with complicated diverticulitis were more likely to have CRC (adjusted OR 3.57, 95% CI 1.59-8.01).”

Based on their findings, the authors concluded that the risk of CRC is low in most patients with diverticulitis; however, patients with complicated diverticulitis are the exception. The authors also noted that their findings imply that colonoscopy to detect missed CRC should incorporate diverticulitis patients with a complication and those not current with CRC screening.

In a press release on the University of North Carolina (UNC) School of Medicine website, Anne Peery, MD, associate professor of medicine in the division of gastroenterology and hepatology, stated, “We need to understand the risk of missed cancer to inform whether patients with a history of diverticulitis need a follow-up colonoscopy.”

Lead author Walker Redd, MD, clinical outcomes and epidemiology fellow in the division of gastroenterology and hepatology at the UNC School of Medicine, stated, “Individuals who have had a prior colonoscopy performed more recently will be at lower risk for CRC, and those individuals who are undergoing colonoscopy for an indication of diverticulitis may have been more likely to have had a colonoscopy performed more recently than those undergoing colonoscopy for screening which likely explains why the risk of CRC was lower among patients with diverticulitis.”

Dr. Reed also stated, “The appearance of complicated diverticulitis is more similar to the appearance of a CRC on a CT scan, so it is more likely that a CRC could be mistaken for complicated diverticulitis. This likely explains why those patients with complicated diverticulitis are more likely to have CRC found on colonoscopy.”

“In older patients with diverticulitis, follow-up colonoscopy should include consideration of the patient’s overall health status, whether alarm symptoms are present, family history of CRC, findings on any prior colonoscopies, and any notation of concern on imaging,” stated Dr. Peery.

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