[Colonoscopy demand estimation for population-based colorectal cancer screening using fecal immunochemical test in Chile]

Colorectal cancer (CRC) screening based on fecal occult blood testing (FOBT) has demonstrated effectiveness in multiple studies.

To estimate the potential demand for colonoscopy generated by a single-sample qualitative fecal immunochemical test (FIT) in the FONASA beneficiaries aged 50-75 years using data from the 2016-2017 Chilean National Health Survey (ENS).

A prevalence study was conducted in a representative subsample of FONASA beneficiaries aged 50-75 years. Participants underwent a single-sample qualitative FIT. The prevalence of positive FIT results was compared across different groups, and multivariable models were constructed adjusting for sex, age, urban/rural residence, health insurance status, body mass index (BMI), alcohol consumption, tobacco use, and family history of CRC.

A total of 892 individuals were included (97.8% test return rate), mean age of 60.52 years (SD 0.40); 53.71% were women, and 3.22% reported a family history of CRC. The prevalence of lower gastrointestinal bleeding during the previous three months was 10.22%, while 36.86% reported a change in bowel movements. FIT positivity was 17.46% (95% CI: 14.07-21.29), with no significant differences according to sex, family history of CRC, or reported symptoms. The estimated colonoscopy demand corresponds to 440,443 individuals.

Implementation of a FIT-based CRC screening strategy would require a substantial increase in colonoscopy capacity in Chile to meet the additional demand generated within the target age group, with heterogeneous distribution across regions.