Re-use of fecal immunochemical test (FIT) devices for associations of colorectal neoplasia with fecal microbiome metrics: A population-based cross-sectional study

Background: Cross-sectional studies suggest that alteration of the colon's microbial population (microbiota) probably contributes to risk for colorectal adenoma (CRA) and progression to cancer (CRC). Cost-effective, unbiased collection of feces from large populations is required for prospective studies. Professionally collected fecal immunochemical test (FIT) devices have yielded good microbiome metrics.Conclusions: With at-home collection of FIT, mailed and tested for routine CRA/CRC screening, only 61% of the devices yielded satisfactory microbiome profiles. CRA/CRC had expected associations with male sex and overweight/obesity, but not with microbiome metrics. Possible reasons for null associations include sparse feces, degradation, low-grade contamination, and insufficient statistical power.