Calls for improved colorectal polypectomy training and quality assurance monitoring have been made by US researchers after they found incomplete resection  increased the risk of neoplasia recurrence.

Their study of 166 patients with previous neoplastic polyp (5–20 mm) resections showed there were 32 patients with at least one incompletely removed neoplastic study polyp. Incomplete resections were three times more likely to have metachronous neoplasia at follow-up colonoscopy (odds ratio [OR]: 3.02, CI: 1.12–8.17) compared to complete resections.

These patients also had a shorter time to surveillance colonoscopy, the authors wrote in Annals of Internal Medicine, with incomplete resection patients returning at median 17 months versus 45 months for those with complete resections.

Patients had a greater risk of developing metachronous neoplasia (52% vs 23%, risk difference [RD]: 28% [95% CI: 9–47%], P = 0.004) and advanced neoplasia (18% vs. 3%, RD: 15%, CI, 1–29%, P = 0.034) in colon segments with incomplete resections than those with complete resections.

They also developed more polyps in those segments (mean: 0.8 vs 0.3, RD: 0.50, CI: 0.1–0.9, P = 0.008).

Incomplete polyp resection was thought to account for 10–30% of all postcolonoscopy colorectal cancer, the authors wrote, though the evidence linking them was indirect. They said definitive evidence to show the clinical importance of incomplete resection would need to come from studies that have objectively proven incomplete lesion removal with reexamination of the resection site within several years of the initial polypectomy.

“The direct evidence from this study strongly supports the hypothesis that residual neoplasia from incompletely removed polyps is a likely contributor to neoplasia recurrence and, by extension, interval colorectal cancer. The results highlight the critical importance of polyp resection technique in efforts to improve colonoscopy quality,” they said.

However, despite the importance of complete polyp resection and its standing as a colonoscopy quality marker, incomplete resection rates in clinical practice remained high, the authors noted.

In a recent meta-analysis, 16% of 1- to 10-mm polyps and 21% of 10- to 20-mm polyps were incompletely removed. The authors suggested this may be partly due to the size and number of polyps in some patients, as larger and greater numbers of polyps may be harder to completely resect.

Therefore, “further work to improve polypectomy technique through training and quality assurance type monitoring is warranted,” they advised.