CHICAGO—Previously manipulated colorectal polyps should be referred for definitive endoscopic mucosal resection within six weeks, according to a study that found worse outcomes after a longer interval from the index colonoscopy.

“A delay of more than six weeks in achieving a definitive resection from the index colonoscopy is associated with a greater risk of fibrosis, and the presence of visible fibrosis is associated with worse outcomes,” said Grace E. Kim, MD, a second-year gastroenterology fellow at the University of Chicago.

This is the first research exploring outcomes related to timing in EMR, according to Dr. Kim. “If externally validated, our findings support expedited definitive resection for previously manipulated lesions.”

Outcomes Have Been Unclear

As Dr. Kim pointed out, the U.S. Multi-Society Task Force on Colorectal Cancer recommends referral to an endoscopist who is experienced in advanced polypectomy for management of large colorectal polyps. Prior manipulation of polyps—such as biopsy, attempted resection or tattoo placement—increases the risk for fibrosis and adverse outcomes, including incomplete EMR (Clin Gastroenterol Hepatol 2019;17[1]:16-25.e1).

Noting that “delays often occur with ... making referrals and with scheduling repeat colonoscopy,” she said “it has not been clear whether the time from manipulation to resection affects the presence of fibrosis and resection outcomes.”

To evaluate whether the timing of this final EMR is important for an optimal outcome, Dr. Kim and her co-investigators used a prospectively maintained procedure database at a tertiary referral center to identify patients undergoing EMR between 2016 and 2021. The researchers reviewed index colonoscopy reports and included only previously manipulated polyps larger than 10 mm in size referred for EMR in the analysis. They then retrospectively collected data on the patients, polyps, procedures and outcome-related variables; calculated the timing between index colonoscopy and definitive resection; and compared polyps referred and resected within six weeks with those referred and resected after six weeks.

Inclusion criteria were met by 245 patients, including:

• 201 with prior biopsy; 76 (38%) also had tattoos, and 19 of those tattooed (25%) had a tattoo extending to the base of the lesion;
• 29 with prior resection attempts; 13 (45%) also had tattoos, and two of those tattooed (15%) had a tattoo extending to the base of the lesion; and
• 15 with tattoos only; one (6.7%) had the tattoo extending to the base of the lesion.

There were no significant differences in patient demographics, polyp location or size, Paris classification, or histology between the two groups.

Longer Interval, More Problems

Of the 245 patients, 62 (25.3%) had fibrosis noted on the endoscopy report. Mean time between index colonoscopy and definitive resection was 9.1 weeks. At the six-week interval, a highly statistically significant effect on EMR outcomes was observed, Dr. Kim reported at Digestive Disease Week 2023 (abstract 590).

Of note, previously manipulated polyps referred and resected within six weeks had a significantly lower incidence of visible fibrosis (19.2% vs. 31.3%; P=0.030). In the multivariate analysis controlling for polyp size, the odds of visible fibrosis were 49% lower for these patients (P=0.028).

Polyps with visible fibrosis were associated with worse outcomes, including longer procedure time (72 vs. 52 minutes; P<0.0001), lower Sydney resection quotient (3.9 vs. 8.2; P=0.001) and lower rates of en bloc resection (9.7% vs. 22.4%; P=0.028). There were no significant differences in adverse events or recurrence rates between the groups.

Early Interventions, Prior Findings Play a Role

Dr. Kim acknowledged the limitations of her study: It was a retrospective analysis of a tertiary referral population treated at a single center, with varying EMR techniques and with the presence of fibrosis noted based on endoscopic inspection only (without a standardized assessment tool). Future research, she said, should include a multicenter prospective study with a cutoff defined a priori.

Heiko Pohl, MD, a professor at the Geisel School of Medicine at Dartmouth, in Lebanon, N.H. pointed out several other limitations of the study. He said prior findings or interventions probably affected the subsequent findings more than the time to repeat endoscopy, but these data were not available or reported. It would be important to know whether the prior intervention involved just one “biopsy bite” and whether the lesion was injected but did not lift (and was referred for this reason without any resection attempts). The choice of the six-week threshold was also arbitrary, he noted. “Any of these earlier interventions will likely affect the ease for completing the resection at a second colonoscopy,” he said.

However, he emphasized the importance of looking at delays in endoscopic care. “The study, therefore, is relevant. … While the best timing remains unclear, the results suggest that a completion polyp resection should be done sooner rather than later.”

—Caroline Helwick

Drs. Kim and Pohl reported no relevant financial disclosures.