Abstract

Background
/Aims: The aim of this study was to evaluate the characteristics of colorectal polyps, especially distal colorectal polyps and their frequency in patients with colon cancer located proximal to the splenic flexure. Methods: Among 1,250 patients with colorectal cancer, 269 patients (21.5%) had colon cancer located proximal to the splenic flexure. Of these, 183 patients were involved in this study because complete colonoscopic evaluations to the cecum or to the level of proximal colon cancer were possible. Results: 54 patients (29.5%) had one or more distal colorectal polyps, 33 patients (18.1%) had one or more adenomatous distal polyps, and 3 patients (1.6%) had synchronous distal carcinoma. The percentage of patients without distal polyps was 70.5% of 183 patients with proximal colon cancer, and 80.3% of patients without distal neoplastic lesions. The percentage of patients with advanced lesions (villous component, high-grade dysplasia, or ≥1 cm in diameter) was 40.7% of 54 patients with distal colorectal polyps. Conclusions: Flexible sigmoidoscopy is insensitive and ineffective for the detection of proximal colon cancer. Ongoing evaluation of colonoscopy as a general screening test is appropriate.

• Keywords: Proximal colon cancer, Flexible sigmoidoscopy, Colonoscopy, Screening test