The management of small polyps found by virtual colonoscopy: results of a decision analysis

There is a firm consensus that larger (> or =10 mm) colonic polyps should be removed; however, the importance of removing smaller polyps (<10 mm) is more controversial. If computed tomographic colonography (CTC) is used for colorectal cancer screening, the majority of polypoid lesions identified will be less than 10 mm in size. Decision-analytic techniques were used to compare the outcomes of 2 management strategies for smaller (6-9 mm) polyps discovered by CTC.

Hypothetic average-risk patients who had undergone a CTC examination and found to have a small (6-9 mm) polyp were simulated to either: (1) undergo immediate colonoscopy for polypectomy (COLO), or (2) wait 3 years for a repeat CTC examination (WAIT). A Markov model was constructed to analyze outcomes including the number of deaths and cancers after a 3-year follow-up period or time horizon. Values for the model parameters were derived from the published literature and from Surveillance Epidemiology and End Results data, and an extensive sensitivity analysis was performed.

The COLO strategy resulted in 14 total deaths per 100,000 patients compared with 79 total deaths in the WAIT strategy, for a difference of 65 deaths. The COLO strategy resulted in 39 cancers per 100,000 patients vs 773 in the WAIT strategy, for a difference of 734 cancers. Sensitivity analysis found that model findings were robust and only sensitive at extreme parameter values.

Managing smaller polyps detected on a screening CTC with another CTC examination 3 years later likely will result in more deaths and cancers than immediate colonoscopy and polypectomy.