Colorectal cancer risk higher after incomplete polyp resection

A follow-up analysis of patients who had a 5- to 20-mm neoplastic polyp resected found significantly greater risk of advanced neoplasia on their next colonoscopy if the resection was incomplete.

Incomplete resection of a neoplastic polyp is associated with increased risk of future neoplasia, a recent study found.

The observational cohort study included 166 patients who had resection of a 5- to 20-mm neoplastic polyp as part of the Complete Adenoma Resection study and underwent at least one surveillance examination after resection, meaning there were 996 colon segments for study. Of the patients included in follow-up, 32 had at least one incompletely removed study polyp, and 134 had only completely removed study polyps. Results were published by Annals of Internal Medicine on Aug. 10.

For patients with a documented incomplete polyp resection on marginal biopsy, a surveillance examination within a year was recommended. Accordingly, the median time to surveillance was shorter after incomplete versus complete resection (17 vs. 45 months). However, the risk for any metachronous neoplasia was greater in segments with incomplete versus complete resection (52% vs. 23%; risk difference [RD], 28% [95% CI, 9% to 47%]; P=0.004). Incomplete segments also had a greater mean number of neoplastic polyps (0.8 vs. 0.3) and greater risk for advanced neoplasia (18% vs. 3%). Incomplete resection was the strongest independent factor for metachronous neoplasia (odds ratio, 3.0; 95% CI, 1.12 to 8.17).

The authors noted several limitations to the study, including the possibility that differences in patients and polyps at baseline could have confounded the results, but they concluded that the study showed a statistically significantly greater risk for future neoplasia and advanced neoplasia in colon segments that had incomplete resection.

“These results highlight the importance of achieving complete resection,” they wrote, noting that the size of polyps found after incomplete resection within a generally short follow-up time implied abnormally fast growth. “One possible explanation is that incomplete electrocautery snare resection may have a proliferating effect and stimulate growth. If this were true, one would expect to see a greater metachronous recurrence after ‘hot’ electrocautery resection compared with ‘cold’ resection without electrocautery; further study is needed,” they wrote.