The impact of aspirin and statin usage on the likelihood of advanced neoplasia at colonoscopy following a positive FOB screening test.

Abstract

346 Background: There is increasing evidence that non-steroidal anti-inflammatory drugs, in particular aspirin, and statins can reduce the incidence and progression of colorectal cancer. However, studies examining this relationship within colorectal cancer screening are limited. Therefore the aim of the present study was to assess the impact of aspirin and statins on an individual’s risk of advanced neoplasia in a colorectal cancer screening programme. Methods: A prospectively maintained database of all patients in the first round of screening (April 2009 to March 2011) in our geographical was analysed. Medication usage was recorded prospectively at pre-colonoscopy assessment. The outcome measure was advanced neoplasia, which was defined as cancer or an intermediate or high risk adenomata (>2 polyps, or > 1 polyp >1cm). Results: 4,631 individuals underwent colonoscopy following a positive FOBt of which complete results were available for 4,188 (90%) pts. Overall, 657 (16%) were on aspirin, 880 (21%) were on statins and 537 (13%) were on both. Colorectal pathology was associated with a positive FOBt in 3,043 (73%) pts. Aspirin usage was associated with a reduced likelihood of colorectal pathology being identified (OR 0.79 (0.66-0.95) p=0.012). In the 3,043 pts in whom colorectal pathology was identified, advanced neoplasia was seen in 1,704 (56%) pts. Patients with advanced neoplasia were more likely to be older (OR 1.38 (1.19-1.59)) and male (OR 1.66 (1.43-1.94)) (both p<0.001). In contrast, those on aspirin (OR 0.68(0.56-0.83)), statins (OR 0.65 (0.55-0.78)) or both (OR 0.69 (0.55-0.86)) were less likely to have advanced neoplasia at colonoscopy (all p<0.001). On multivariate analysis, use of both aspirin and statins (OR 0.60 (0.48-0.75) p<0.001) remained independently associated with less advanced neoplasia. Conclusions: In patients undergoing colonoscopy following a positive FOBt with documented evidence of statin or aspirin usage, advanced neoplasia was less likely to be found. This suggests that usage of these medications may have a chemopreventative effect within the context of screening for colorectal cancer.