2025/07/28 Colorectal Cancer Screening: New Study Supports Starting at Age 40

A large-scale study from Taiwan has provided compelling evidence that initiating colorectal cancer screening at age 40 can significantly reduce both cancer incidence and mortality. Published in JAMA Oncology, the study was led by Professor Han-Mo Chiu of National Taiwan University College of Medicine in collaboration with Professor Hsiu-Hsi Chen of the College of Public Health. Drawing on data from over half a million adults aged 40 to 49 in Keelung and Tainan, the research followed participants for 17 years under a community-based screening program using the fecal immunochemical test (FIT).
 
The analysis showed that individuals who began FIT screening in their 40s and continued into their 50s experienced markedly lower rates of colorectal cancer compared to those who waited until age 50 to start screening. After adjusting for demographic and behavioral factors, early screening was associated with a 21 to 25 percent reduction in cancer incidence and a 34 to 39 percent reduction in mortality. The findings also indicate greater screening efficiency when started earlier, with fewer individuals needing to be screened to prevent one case of cancer.
 
The study has attracted international attention and was accompanied by an invited commentary from Harvard researchers in the same journal issue, who highlighted the work as important evidence to inform screening guidelines, particularly in the absence of randomized trials. The results are consistent with the U.S. Preventive Services Task Force’s decision in 2021 to lower the recommended starting age for colorectal cancer screening to 45, and further suggest that East Asian populations may benefit from even earlier intervention.
 
As colorectal cancer continues to rise among younger age groups in Taiwan—now ranking among the top three cancers for both men and women in their 40s—this study supports timely and region-specific adjustments to public health policy. Taiwan’s decision to lower the screening age to 45 in 2025 reflects a proactive approach grounded in local evidence.
 
https://jamanetwork.com/journals/jamaoncology/fullarticle/2835051