Rank-Based Fecal Hemoglobin Concentration for Assessing Colorectal Neoplasms of National-Wide Colorectal Cancer Screening in Taiwan

Background: Fecal hemoglobin concentration has shown potential of predicting colorectal cancer and colorectal adenoma. Accordingly, it is of great interest to use fecal hemoglobin concentration to stratify population into risk groups of colorectal disease. Aim: This study aims to predict the risk of colorectal neoplasia by using quantitative fecal hemoglobin concentration with a rank-based method. Methods: Using data from Taiwanese nationwide colorectal cancer screening program between 2004 to 2009 following up until 2012, fecal hemoglobin concentration regarded as the ordinal outcome was used to predict the risk of colorectal adenoma. Accelerated failure time model on fecal hemoglobin was used to evaluate the differences across 4 categories of outcome, including colorectal cancer, advanced adenoma, nonadvanced adenoma, and normal colon. We converted the adjusted percentile values of each group of colorectal neoplasia into the corresponding risk with Bayesian underpinning. Results: The adjusted median fecal hemoglobin concentration of nonadvanced adenoma was 57.0, advanced adenoma was 82.4, and colorectal cancer was 163.1 µg/g feces compared with normal colon. The corresponding risks of 2 groups when the fecal hemoglobin concentration reached the median were 4.0%, 4.8%, and 29.5%. Risk of reaching other percentile of 2 groups of colorectal neoplasm can be acquired on the basis of adjusted percentile value of fecal hemoglobin. Conclusion: Based on quantitative fecal hemoglobin concentration and survival model analysis, we estimated the risk of developing colorectal neoplasia by percentile of fecal hemoglobin concentration.