Impact of the consideration of serrated polyps to the interval of colonoscopic surveillance in the NHS Bowel Cancer Screening Programme

Aim Most international post polypectomy surveillance guidelines do not recommend surveillance for serrated polyps. In the present study the additional impact of serrated polyps on surveillance intervals from international adenoma surveillance guidelines was investigated. Method Endoscopic and pathology records were audited of participants in the NHS Bowel Cancer Screening Programme (guaiac faecal occult blood test, gFOBT) in 2011. Surveillance intervals were calculated for current guidelines and also for serrated polyps based on previously described aggressive and conservative strategies. Results In total, 389 patients were included of whom 141 (36.2%) were high risk (advanced adenoma: adenoma >= 10 mm, villous elements, high grade dysplasia, or adenoma >= 3 in number) needing surveillance at <= 3 years. Thirty-three (8.5%) had significant serrated polyps, of whom 18 (4.6% of the total) had significant serrated lesions and simultaneous advanced adenoma or >= 3 adenomas. Adopting an aggressive surveillance strategy, the mean overall absolute additional proportion of all such patients in the surveillance group at 3 years or less was 4.0% (3.9% - 4.1%; 4.2% women; 3.8% men). These proportions varied according to endoscopist from 2.3% to 4.7%. For more conservative strategies the increase was only 1%. Conclusion The impact of including serrated polyps in current guidelines would result in a small increase in surveillance intervals for FOBT based bowel cancer screening. About half of those who might need surveillance for serrated polyps would already receive surveillance for being in a high risk adenoma group.