The comparison of the risk factors and clinical manifestations of proximal and distal colorectal cancer

PURPOSE: Colorectal cancers in the proximal or distal site have distinct clinical characteristics. In this study, the authors compared the risk factors of proximal and distal colorectal cancer. METHODS: A 16-page questionnaire was administered to 529 patients with colorectal cancer before operation. Cancers were classified as proximal or distal relative to the splenic flexure. Of these 529 patients, 6 patients were excluded because of the presence of synchronous colorectal cancers. Data of the 523 patients were analyzed. RESULTS: Total numbers of proximal and distal cancers were 123 and 400. The proportion of patients with Type 2 diabetes was significantly higher for distal cancer (P=0.034), whereas a greater proportion of patients with proximal cancer had a gallstone history (P=0.005). Multivariate analysis revealed Type 2 diabetes to be a risk factor for distal colorectal cancer (P=0.027) and cholelithiasis to be a risk factor for proximal cancer (P=0.049). The odds ratio for distal colorectal cancer among males with Type 2 diabetes was 4.1 (95 percent confidence interval, 1.4-12.1). On the other hand, a gallstone history was more associated with proximal colon cancer, especially in females (odds ratio=5.5; 95 percent confidence interval, 1.4-20.9). CONCLUSIONS: A comparison of the risk factors of proximal and distal colorectal cancer showed that Type 2 diabetes is associated with distal colorectal cancer in males and that cholelithiasis is associated with proximal colon cancer in females.