in a case control study , which formed part of a large , population-based investigation of the incidence , aetiology and survival of colorectal cancer , 24 of 715 cases and 4 of 727 age/sex group matched controls gave a past history of bowel polypectomy ( x21 = 17 , p less than 0.001 , relative risk = 6.37 , 95 per cent confidence interval = 2.2-18.6 ) .
C0009402
colorectal cancer
C0021853
bowel