Demand for colonoscopy in colorectal cancer screening using a quantitative fecal immunochemical test and age/Sex-Specific thresholds for test positivity

Sam Li Sheng Chen, Chen Yang Hsu, Amy Ming Fang Yen, Graeme P. Young, Sherry Yueh Hsia Chiu, Jean Ching Yuan Fann, Yi Chia Lee, Han Mo Chiu, Shu Ti Chiou, Hsiu Hsi Chen

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Background: Despite age and sex differences in fecal hemoglobin (f-Hb) concentrations, most fecal immunochemical test (FIT) screening programs use population-average cut-points for test positivity. The impact of age/sex-specific threshold on FIT accuracy and colonoscopy demand for colorectal cancer screening are unknown. Methods: Using data from 723,113 participants enrolled in a Taiwanese population-based colorectal cancer screening with single FIT between 2004 and 2009, sensitivity and specificity were estimated for various f-Hb thresholds for test positivity. This included estimates based on a "universal" threshold, receiver-operating-characteristic curve–derived threshold, targeted sensitivity, targeted false-positive rate, and a colonoscopy-capacity-adjusted method integrating colonoscopy workload with and without age/sex adjustments. Results: Optimal age/sex-specific thresholds were found to be equal to or lower than the universal 20 mg Hb/g threshold. For older males, a higher threshold (24 mg Hb/g) was identified using a 5% false-positive rate. Importantly, a nonlinear relationship was observed between sensitivity and colonoscopy workload with workload rising disproportionately to sensitivity at 16 mg Hb/g. At this "colonoscopy-capacity-adjusted" threshold, the test positivity (colonoscopy workload) was 4.67% and sensitivity was 79.5%, compared with a lower 4.0% workload and a lower 78.7% sensitivity using 20 mg Hb/g. When constrained on capacity, age/ sex-adjusted estimates were generally lower. However, optimizing age/-sex-adjusted thresholds increased colonoscopy demand across models by 17% or greater compared with a universal threshold. Conclusions: Age/sex-specific thresholds improve FIT accuracy with modest increases in colonoscopy demand. Impact: Colonoscopy-capacity-adjusted and age/sex-specific f-Hb thresholds May be useful in optimizing individual screening programs based on detection accuracy, population characteristics, and clinical capacity. Cancer Epidemiol Biomarkers Prev; 27(6); 704–9. 2018 AACR.

Original languageEnglish
Pages (from-to)704-709
Number of pages6
JournalCancer Epidemiology Biomarkers and Prevention
Issue number6
Publication statusPublished - Jun 2018

ASJC Scopus subject areas

  • Medicine(all)


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