Association of FOBT-assessed faecal Hb content with colonic lesions detected in the Florence screening programme

We assessed the correlation between quantitative results of immunological faecal occult blood testing (I-FOBT) and colonic lesions (191 colorectal cancers, 890 adenomas) detected at colonoscopy in 2597 FOBT + (cutoff 100 ng ml(-1) Hb) subjects. At univariate analysis, a higher average faecal Hb content was significantly associated with male gender (P = 0.003), age (P = 0.02), and colonoscopy findings (P = 0.000). Among adenomas, higher faecal Hb content was significantly associated with size (P = 0.0000), presence of severe dysplasia (P = 0.0001), presence of villous component (P = 0.0002), and location in the left colon (P = 0.003). At multivariate analysis adjusting for potential confounders, age (P = 0.03), size (P = 0.0000), and location in the left colon (P = 0.0005) were confirmed as having an independent association with higher faecal Hb content. Immunological FOBT is confirmed to be a specific screening test to detect cancer and adenoma, with a low positivity rate (3.7%) and a high positive predictive value (41.5%). Faecal Hb content is significantly higher for those lesions (cancer and high-risk adenomas) screening is aimed at detecting.