PROGNOSIS OF COLORECTAL-CANCER VARIES IN DIFFERENT HIGH-RISK CONDITIONS

Variation in prognosis between different colorectal cancer (CRC) patie nt groups was studied by comparing the survival rates of patients belo nging to three cancer predisposition groups with those with sporadic C RC. The high-risk groups included 43 members of hereditary nonpolyposi s colorectal cancer (HNPCC) families, 25 patients with familial adenom atous polyposis (FAP) and 33 patients with underlying ulcerative colit is (UC). The control group included 122 consecutive sporadic CRC patie nts. Cumulative 5-year survival was highest in HNPCC (86%), which is s ignificantly better than in sporadic colorectal cancer (59%, hazard ra tio 0.41, P = 0.02). Cancer associated with UC had a 5-year survival r ate of 39%, which is significantly less than in sporadic cancer (hazar d ratio 1.83, P = 0.03). There was no significant difference in the su rvival between patients with FAP and patients with sporadic CRC (hazar d ratio 1.27, P= 0.5). Exclusion of cases detected by screening examin ations slightly reduced the survival rates; 85% for HNPCC, 53% for FAP and 28% for UC. However, the differences between the groups remained significant. The survival of patients with HNPCC was found to be bette r than that among other groups in this study, which probably relates t o the specific tumourigenesis involving DNA mismatch repair dysfunctio n.