Fahad Mir, MD, MSc, on Adenoma Detection in the Right Colon
A 6-minute withdrawal time during screening and surveillance colonoscopy—the standard of care—has been known to improve adenoma detection rate (ADR), a quality measure for colonoscopies.
Still, the miss rate for adenomas can remain as high as 30%; lesions on the right side of the colon are most at-risk for being missed. The ideal withdrawal time for examining the right colon was previously unknown.
Fahad Mir, MD, MSc, advanced endoscopy fellow at Beth Israel Deaconess Medical Center in Boston is the lead author of a new study1 presented at the American College of Gastroenterology’s Annual Meeting 2018 about the topic and answered our questions about the outcomes of his research.
Gastroenterology Consultant: How did your study come about?
Fahad Mir: There is an abundance of literature suggesting that the risk of missing lesions in the right side of the colon is high. The ADR is highly variable, and in a large study it was shown that it can vary between 7.4% and 52.5% among gastroenterologists.
We also know from previous research that each 1% increase in ADR is associated with a 3% decrease in risk of colorectal cancer and a 5% decrease in mortality related to colorectal cancer. Therefore, to improve ADR, several devices, techniques, and guidelines have been implemented. Among these interventions is using a 6-minute withdrawal during screening and surveillance colonoscopy. Given that right-sided lesions are at high risk of being missed, we hypothesized that spending longer in the right side of the colon will also help improve ADR.
GASTRO CON: Why are lesions on the right side of the colon at high risk of being missed during a colonoscopy?
FM: Colonoscopy can reduce incidence and mortality from colon cancer by 80% in the left side of the colon but only about 40% to 60% in the right side of the colon. Several risk factors have been implicated, including difficulty with maneuverability and examining behind the fold of the right side of the colon. There is also a higher rate of flat lesions—sessile serrated adenomas—in the right side of the colon. Identifying these lesions under white light is more difficult compared with polypoid lesions.
GASTRO CON: The results of your study showed that the ADR was higher if the right colon withdrawal time was 3 minutes or longer. What are the clinical implications of your study that gastroenterologists can apply in the future?
FM: Total withdrawal time of 6 minutes during colonoscopy is standard of care. If half of that time is spent during right colon withdrawal (cecum and ascending colon), our study showed that it would significantly improve ADR in the right colon. We also showed that total ADR improves as well. I believe that if gastroenterologists apply this in their practice, it will improve ADR without overtly prolonging duration of the procedure. This will help improve colon cancer prevention.
GASTRO CON: What is the next step in your research?
FM: We are looking to further study the efficacy of an Artificial Intelligence platform on ADR, in addition to these standards of withdrawal times. We are hoping to show this would further improve ADRs.
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Reference:
1) Mir FF, Badar H, Shafiq M, et al. Examination of the right colon for three minutes or more significantly increases adenoma detection rate: A multi-center prospective randomized controlled trial. Paper presented at: American College of Gastroenterology Annual Meeting 2018; October 5-10, 2018; Philadelphia, PA. https://www.eventscribe.com/2018/ACG/. Accessed October 22, 2018.