Risk-stratified selection to colonoscopy in FIT colorectal cancer screening: development and temporal validation of a prediction model

Abstract

BACKGROUND: Faecal immunochemical tests (FITs) yield many false positives and challenge colonoscopy capacity in colorectal cancer (CRC) screening programmes. We aimed to develop a risk-based selection of participants to undergo diagnostic colonoscopy. METHODS:The study was observational and used registry data from the Danish CRC screening programme. We included all participants invited 2014-2016 with a positive FIT (≥ 20 μg fHb/g) who underwent colonoscopy (n = 56,459). We predicted the risk of CRC or advanced neoplasia (AN) from age, gender and FIT value using logistic regression. We evaluated calibration and discrimination and conducted temporal validation. We compared the number of CRCs and adenomas identified by risk cut-offs and by a corresponding FIT cut-off. RESULTS: AUCs were 74.9% (95% CI: 73.6; 76.3) and 67.4% (95% CI: 66.8%; 68.0%) for the models predicting CRC and AN in the validation dataset. The cut-off of CRC risk calculated from age, gender and FIT value identified 1.03 times (95% CI: 1.02; 1.05) more CRCs and 1.01 times (95% CI: 1.01; 1.01) more medium/high-risk adenomas compared with the corresponding FIT cut-off. CONCLUSIONS: With existing data, risk-stratified FIT screening using a risk cut-off instead of a FIT cut-off can slightly improve the selection to colonoscopy of those at highest risk of cancer and adenomas.

Risk scoring systems for predicting presence of colorectal neoplasia by fecal immunochemical test results in Chinese population

“…The LR-based FIT-specific scoring systems also performed well in predicting CRC and adenoma, with an AUC of 0.660. The AUC of our systems was within the AUCs of 0.62–0.75 for other scoring systems in predicting advanced colorectal neoplasia ( 20 , 21 , 31 , 38 , 39 ) and slightly higher than 0.62 of a scoring system for both advanced and nonadvanced neoplasia ( 40 ). Similar to previous studies ( 20 , 21 ), however, our systems for colorectal neoplasia were derived from high-risk individuals who attended colonoscopy and thus cannot be directly applied to general populations.…”

“…The AUC of our systems was within the AUCs of 0.62–0.75 for other scoring systems in predicting advanced colorectal neoplasia ( 20 , 21 , 31 , 38 , 39 ) and slightly higher than 0.62 of a scoring system for both advanced and nonadvanced neoplasia ( 40 ). Similar to previous studies ( 20 , 21 ), however, our systems for colorectal neoplasia were derived from high-risk individuals who attended colonoscopy and thus cannot be directly applied to general populations. Moreover, due to lack of detailed information to distinguish advanced adenoma from those nonadvanced, we used CRC and all adenomas as the outcomes, which is not consistent with those having using CRC and advanced adenomas as outcomes ( 31 , 33 ).…”

“…In this study, for the first time, we developed FIT-specific scoring systems for CRC and colorectal neoplasia and provided tailored risk assessment tools to identify individuals with possible bleeding or nonbleeding colorectal lesions. With an AUC of more than 0.800 in identifying CRC, the FIT-specific scoring systems, either LR-based or ANN-based, outperformed those in previous studies demonstrating an AUC of 0.53–0.75 ( 20 , 33 , 36 ), including the parallel use of risk stratification and FIT in the Shanghai CRC screening program. The higher specificity, less demand for colonoscopy, and less colonoscopies needed to detect 1 CRC of the FIT-specific scoring systems suggest the value of our systems in reducing unnecessary colonoscopies ( 37 ), improving adherence to colonoscopy ( 8 ), and thus replacing the parallel use of risk stratification and FIT.…”

“…There exist different risk factors for bleeding and nonbleeding colorectal neoplasia. A family history of CRC was associated with advanced colorectal neoplasia among FIT-negative subjects ( 18 , 19 ), but not identified as a risk factor among FIT-positive populations ( 20 , 21 ). These findings justify the need for tailored risk scoring systems according to FIT results.…”

“…Although the risk factors significantly differed between subjects positive in FIT and those negative ( 19 , 34 , 35 ), no predictive model was specifically developed by the test results. So far, only 2 models have been established for FIT-positive subjects by integrating FIT concentration and other factors to predict the outcome of CRC or advanced neoplasia ( 20 , 21 ).…”