Introduction The St Mark's Bowel Cancer Screening Centre (BCSC) rolled out between 2006 and 2007. To date, 1200 colonoscopies have been performed by five accredited screening endoscopists. The programme is now into its third year and therefore second year of surveillance for high-risk patients.

Methods To review the polyp surveillance procedures performed between Oct 2006 and July 2009. Data regarding the timing, number and size of polyps were collected prospectively.

Result 1200 colonoscopies were performed between October 2006 and July 2009. 67 were 1-year polyp surveillance procedures (64 for high-risk polyps, two for intermediate risk, one for polyp cancer). There were 6.0 (3.76) polyps found per index procedure and 3.0 (2.4) per surveillance procedure (p<0.0001). In three cases, there were more polyps seen at surveillance than in the index procedure. Polyp size in the index procedure was 18.1 mm (11.8) compared to 5.26 mm (2.99) in the surveillance group (p<0.0001). Three of the 67 surveillance procedures revealed polyps >1 cm (11–16 mm). In two procedures there was an increase in the size of the largest polyp seen (9 mm to 14 mm and 6 mm to 9 mm). In 26 cases, the findings downgraded the risk from high to intermediate and in 30 cases, to low risk. In 11 cases, the risk remained high based on the number and size of polyps. Histologically all were tubular adenomas with low grade dysplasia.

Conclusion In the majority of cases (62 (92%)) there was a reduction in both the size and number of polyps seen at 1-year surveillance. However, in a small number of cases there were significant polyp findings.