Predictive Modeling of Colonoscopic Findings in a Fecal Immunochemical Test-Based Colorectal Cancer Screening Program

Abstract

Background The fecal immunochemical test (FIT) is the primary modality used by the Los Angeles County Department of Health Services (LADHS) for colorectal cancer (CRC) screening in average-risk patients. Some patients referred for FITpositive diagnostic colonoscopy have neither adenomas nor more advanced pathology. We aimed to identify predictors of false-positive FIT (FP-FIT) results in our largely disenfranchised, low socioeconomic status population. Methods We conducted a retrospective study of 596 patients who underwent diagnostic colonoscopy following a positive screening FIT. Colonoscopies showing adenomas (or more advanced pathology) were considered positive. We employed multiple logistic and linear regression as well as machine learning models (MLMs) to identify clinical predictors of FP-FIT (primary outcome) and the presence of advanced adenomas (secondary outcome). Results Overall, 268 patients (45.0%) had a FP-FIT. Female sex and hemorrhoids (odds ratios [ORs] 1.59 and 1.89, respectively) were associated with increased odds of FP-FIT and fewer advanced adenomas (β = − 0.658 and − 0.516, respectively). Conversely, increasing age and BMI (ORs 0.94 and 0.96, respectively) were associated with decreased odds of FP-FIT and a greater number of advanced adenomas (β = 0.073 and 0.041, respectively). MLMs predicted FP-FIT with high specificity (93.8%) and presence of advanced adenoma with high sensitivity (94.4%). Conclusion Increasing age and BMI are associated with lower odds of FP-FIT and greater number of advanced adenomas, while female sex and hemorrhoids are associated with higher odds of FP-FIT and fewer advanced adenomas. The presence of the aforementioned predictors may inform the decision to proceed with diagnostic colonoscopy in FIT-positive patients. Keywords Early detection of cancer • Colonoscopy • Adenoma • Colorectal neoplasms • Machine learning • Social class Abbreviations BMI Body mass index GI Gastrointestinal NSAIDs Nonsteroidal anti-inflammatory drugs IQR Interquartile range * Jade Law

Stool-Based Colorectal Cancer Screening Test Performance Characteristics in Those With and Without Hemorrhoids

“…Similarly, a retrospective study by Law et al 8 supported increased odds of a false-positive FIT given the presence of hemorrhoids on the basis of multiple logistic regression, although a history of hemorrhoid-associated bleeding was unknown. 8 Lack of firm awareness of hemorrhoid-associated bleeding may be more typical of the real-world, but this does not lend greater strength to study conclusions if known or measured.…”

“… 7 By contrast, a more recent study found that hemorrhoids were associated with higher odds of a false-positive FIT. 8 …”

Colon Cancer Screening Methods: 2023 Update

“…This study showed that hemorrhoids and female sex were linked with higher odds of FP-FIT and fewer advanced adenomas, whereas increasing age and body mass index were associated with lower odds of FP-FIT and more advanced adenomas. In FITpositive patients, the choice to perform a diagnostic colonoscopy may be influenced by the existence of the above-mentioned indicators [36]. Such FP-FIT results subject patients to unnecessary colonoscopies, which raises the burden and cost of healthcare, subject patients to unnecessary interventions, decrease adherence to treatment with yearly FIT testing and can cause psychological distress for up to six weeks after a typical colonoscopy [35][36][37].…”

“…In FITpositive patients, the choice to perform a diagnostic colonoscopy may be influenced by the existence of the above-mentioned indicators [36]. Such FP-FIT results subject patients to unnecessary colonoscopies, which raises the burden and cost of healthcare, subject patients to unnecessary interventions, decrease adherence to treatment with yearly FIT testing and can cause psychological distress for up to six weeks after a typical colonoscopy [35][36][37].…”

“…Despite these encouraging figures, neither adenomas nor more severe diseases are present in 39%-52% of individuals who are referred for FIT-positive diagnostic colonoscopy [ 35 , 36 ]. Two hundred and sixty-eight people had a false positive FIT (FP-FIT), according to a retrospective study by Law et al on 596 patients who underwent diagnostic colonoscopy after a positive screening FIT.…”