Utility of Quantitative Fecal Immunochemical Test Values for Average Risk Colorectal Cancer Screening Risk...

Area of Science:

• Gastroenterology
• Oncology
• Medical Diagnostics

Background:

• Fecal immunochemical test (FIT) is a qualitative screening tool for colorectal cancer (CRC).
• Positive FIT results trigger referral for colonoscopy, but many do not have cancer.
• Quantitative FIT (qFIT) values may offer further risk stratification.

Purpose of the Study:

• To evaluate if quantitative fecal hemoglobin concentration (qFIT) values can stratify risk among patients with positive FIT results.
• To determine the relationship between qFIT values and the likelihood of advanced findings upon colonoscopy.

Main Methods:

• Retrospective analysis of 78,555 patients aged 50-75 with positive FIT (≥20 µg/g) undergoing colonoscopy (2013-2022).
• Evaluation of qFIT values in 20 µg/g increments against the most advanced finding at colonoscopy.

Main Results:

• Median qFIT values were higher for CRC (147.8 µg/g) than other findings.
• Positive predictive values (PPVs) for CRC and advanced adenoma increased significantly with higher qFIT values (p<0.001).
• PPV for CRC ranged from 0.9% (20-39.9 µg/g) to 6.7% (≥200 µg/g); PPV for advanced adenoma ranged from 13.4% to 20.4%.

Conclusions:

• Neoplastic findings are present across all qFIT value ranges, underscoring the necessity of colonoscopy for all positive FIT tests.
• Increasing qFIT values correlate with higher PPVs for CRC and advanced adenoma.
• qFIT values can aid in stratifying patients at highest risk for serious neoplastic lesions, particularly in resource-limited settings.