Colonoscopy surveillance for high risk polyps does not always prevent colorectal cancer

Figure 1 Selection of patients included in the determination of colorectal cancer development despite surveillance colonoscopy. ^aPolyp removal between 1/1/2000 12/31/2010 for SSA and TSA for TA, TVA and VA between 1/1/1990 12/31/2010 with follow up complete through 12/31/2016. ^b186 developed both of sessile/traditional serrated and AA. ^cPatients with advanced developed a denoma have at least one the these features (histology with villous component, > 1 cm, or high grade dysplasis). SSA: Sessile serrated adenoma; SSP: Sessile serrated polyp; TSA: Traditional serrated adenoma; TA: Tubular adenoma; VA: Villous adenoma; TVA: Tubulovillous adenoma.

Figure 2 Cumulative incidence of de novo cancers after polypectomy in 4610 patients (A). A: Observed cumulative incidence curves of patients who developed CRC at the same site (dashed lines) and a different site (dashed lines) from the index polyp in year 1, 2 and 3 were 0.3, 0.5, and 0.7 vs 0.17, 0.24, and 0.33, respectively. B: Survival after CRC diagnosis at the same and different site. Kaplan-Meier Curves for Overall Survival among patients who developed CRC at the same site and a different site distinct from the site of the high risk polyp indicates that there is no significant difference between the two groups. C: Cancer location, as compared to removed polyp location in patients who developed CRC in area distinct from polypectomy site of the high risk polyp. From left to right: right colon polyps, left colon polyps, rectal polyps. On Y axis is the number of right colon cancers (blue); left colon cancer (red) and rectal cancer (green).The figure shows that right sided colon cancer was the most frequent location for a cancer to develop in a site distinct from the index polyp regardless of the location for the index polyp.