Abstract
BackgroundAlthough fecal hemoglobin concentration (f-Hb) was highly associated with the risk of colorectal neoplasms, current studies on this subject are hampered by skewedness of the data and the ordinal property of f-Hb has not been well studied yet. Our aim was to develop a quantile-based method to estimate adjusted percentiles (median) of fecal hemoglobin concentration and their derived prediction for the risk of multistage outcomes of colorectal disease.MethodsWe used a 6-year follow-up cohort of Taiwanese nationwide colorectal screening program with fecal immunochemical testing (FIT) to obtain fecal hemoglobin concentration and applied accelerated failure time multi-variable analyses to make the comparison of adjusted median and other percentitles of fecal hemoglobin across four categories of colorectal carcinogenesis. We then predicted the risk of colorectal neoplasms on the basis of the corresponding percentile values by using accelerated failure time model with Bayesian inversion method.ResultsThe adjusted median fecal hemoglobin concentration of nonadvanced adenoma, advanced adenoma, and colorectal cancer were 57, 82, and 163 μg/g feces as opposed to 0 μg/g feces for the normal group. At 90 μg/g of f-Hb, the highly suspected cut-off for colorectal disease, the risks were 17% for non-advanced adenoma, 6% for advanced adenoma, and 9% for CRC. Life-time risks of each colorectal neoplasm were derived by percentiles of fecal hemoglobin concentration.ConclusionCovariate-adjusted risk stratification for multistage outcomes of colorectal neoplasia were provided by using the quantiles of fecal hemoglobin concentration, yielding the estimated life-time risks of 25th to 75th quantitles, ranging from 0.5 to 44% for colorectal cancer, 0.2 to 46% for non-advanced adenoma, and 0.1 to 20% for advanced adenoma.
Highlights
Fecal hemoglobin concentration (f-Hb) was highly associated with the risk of colorectal neoplasms, current studies on this subject are hampered by skewedness of the data and the ordinal property of fecal hemoglobin concentration (f-Hb) has not been well studied yet
Bayesian quantile-based f-Hb for predicting the risk of colorectal neoplasia To take into account the ordinal feature of f-Hb measured by each fecal immunochemical testing (FIT) test as mentioned earlier, we proposed the novel survival methodology with accelerated failure time (AFT) model on quantile-based f-Hb rather than interval-scaled f-Hb
Note that we elucidated the association between quantile f-Hb and colorectal neoplasia based on all data including 10,880 subjects (7814 identified at first screen and 3066 identified at subsequent screens) with non-advanced adenoma, 4604 subjects (3491 identified at first screen and 1113 identified at subsequent screens) with advanced adenoma, 1765 prevalent scree-detected colorectal cancer (CRC), 1608 subsequent screen-detected CRC, and 3247 interval CRC
Summary
Fecal hemoglobin concentration (f-Hb) was highly associated with the risk of colorectal neoplasms, current studies on this subject are hampered by skewedness of the data and the ordinal property of f-Hb has not been well studied yet. Our aim was to develop a quantile-based method to estimate adjusted percentiles (median) of fecal hemoglobin concentration and their derived prediction for the risk of multistage outcomes of colorectal disease. Predicting the risk for colorectal neoplasia using the conventional method that treats the disease status as the outcome and f-Hb as an independent variable with adjustment for relevant factors is not appropriate for the underlying factor (such as f-Hb) that is a part of procedure related to the confirmation of disease as seen in our population-based screening for CRC with FIT that measures f-Hb. we proposed the Bayesian quantile-based survival method to first estimate covariate-adjusted f-Hb50 and f-Hbp values and to asses the life-time risk for the multistages of colorectal neoplasia by percentile-based f-Hb given the baseline risk of each colorectal neoplasm
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