Objective: to evaluate lesions detected in two screening rounds performed in a pilot screening programme for colorectal cancer in Catalonia, Spain.
Material and methods: a colorectal cancer screening programme was initiated in 2000. The target population included men and women aged 50-69 years. Screening consisted of biennial guaiac-based fecal occult blood testing (FOBT), and colonoscopy for participants with a positive FOBT. Any polyps found were removed, and biopsies were performed for any masses.
Results: colonoscopies were performed in 442 of 495 people with positive FOBT. In 213 (48.2%), 36 invasive cancers, 121 high-risk adenomas, 29 low-risk adenomas, and 27 hyperplastic polyps were diagnosed. Lesion size was smaller than 10 mm in 25.8% of cases. Most detected lesions (37.2%) were located in the distal colon, followed by the proximal colon (5.7%) and both locations (5.2%). Advanced neoplasm was significantly associated with male gender and distal location. The prevalence of advanced proximal neoplasms among patients with no distal polyps was 5.1%.
Conclusions: the most common lesions detected by colonoscopy were high-risk adenomas located in the distal colon. FOBT is a suitable method for detecting small precancer lesions during population screening, and is thus a key factor in reducing the incidence of colorectal cancer.