Colorectal cancer screening with the fecal immunochemical test in persons aged 30 to 49 years: focusing on the age for commencing screening

Background and Aims: The fecal immunochemical test (FIT) can be an alternative screening method for colorectal cancer in individuals aged <50 years. However, debate continues concerning the age at which commencing FIT is beneficial. Methods: We reviewed the records of participants who had undergone a colonoscopy and FIT as part of a comprehensive health screening program. To determine the age for commencing screening via FIT, participants aged < 50 years were classified into 4 age subgroups as follows: 30 to 34, 35 to 39, 40 to 44, and 45 to 49 years. Average-risk participants aged 50 to 59 years comprised the control group. Results: We analyzed the data of 19,808 participants aged 30 to 49 years and 2233 average-risk participants aged 50 to 59 years. The advanced colorectal neoplasia (ACRN) prevalence in average-risk participants aged 50 to 59 years was 3.8%. In the subgroups of FIT-positive participants, the proportion of participants with ACRN was 2.9% (95% confidence interval [CI], 1.1%-7.4%), 9.7% (95% CI, 5.8%-15.6%), 7.7% (95% CI, 4.5%-12.8%), and 14.6% (95% CI, 8.7%-23.5%) in groups 30 to 34, 35 to 39, 40 to 44, and 45 to 49 years, respectively. The proportion of FIT-positive participants with ACRN in the groups aged 35 to 39, 40 to 44, and 45 to 49 years was higher than that in average-risk participants aged 50 to 59 years (P = .001, P = .014, and P < .001, respectively), whereas that in FIT-positive participants aged 30 to 34 years was not (P = .566). Conclusion: FIT-positive individuals aged 35 to 49 years had a higher risk of ACRN compared with average-risk individuals aged 50 to 59 years. FIT-positive individuals aged 35 to 49 years may benefit from screening colonoscopy, thus justifying the possibility of commencing FIT from age 35 years.