Starting Colorectal Cancer Screening at Age 40 Cuts Death Risk by 39%, Study Finds

Initiating fecal immunochemical test (FIT) screening for colorectal cancer (CRC) at ages 40 to 49 years—rather than waiting until age 50—led to a 39% reduction in CRC mortality and a 21% reduction in incidence, according to one study.

The community-based cohort study was conducted in Taiwan and was published in JAMA Oncology.

Initiating fecal immunochemical test (FIT) screening before age 50 can significantly reduce colorectal cancer incidence and mortality, according to one study. | Image credit: Paul Maguire - stock.adobe.com

“These findings highlight FIT’s effectiveness in this younger age group and support recommendations to lower the screening initiation age,” wrote the researchers of the study. “Importantly, the long-term benefits of early screening were consistently observed across multiple study designs and statistical adjustments for self-selection bias.”

CRC is increasingly affecting younger populations, with recent data showing sharp rises in diagnoses among children, teens, and young adults.² Since the early 2010s, CRC incidence in individuals under age 50 has been increasing by about 3% each year, and a recent study found a 500% increase in cases among children aged 10 to 14 years over the past 2 decades. Though overall numbers remain low, the rapid rise, later-stage diagnoses, and lack of clear risk factors underscore the urgent need to reexamine screening strategies for younger age groups.

In this recent study, the researchers analyzed data from 263,125 Taiwanese adults aged 40 to 49 years who were eligible for biennial FIT screening as part of a national program.¹ Participants were categorized into 4 subcohorts based on whether they initiated FIT screening early (ages 40 to 49) and whether they continued screening after age 50. The study tracked CRC incidence and mortality through 2019, comparing outcomes between early screeners and those who began screening at age 50.

The study demonstrated that initiating FIT screening between ages 40 and 49 years was associated with a substantial reduction in CRC incidence and mortality compared with starting at age 50. Among the participants, those who received early and continued screening (n = 39,315) had a CRC incidence rate of 26.1 cases per 100,000 person-years (95% CI, 22.3-29.9), compared with 42.6 cases per 100,000 person-years (95% CI, 40.5-44.7) in the group that began screening at age 50 (n = 223,810). Mortality rates were also lower in the early screening group, with 3.2 deaths per 100,000 person-years (95% CI, 1.9-4.6) vs 7.4 (95% CI, 6.5-8.2).

Additionally, propensity score–matched analyses showed a 21% reduction in CRC incidence (adjusted relative risk [aRR], 0.79; 95% CI, 0.67-0.94) and a 39% reduction in mortality (aRR, 0.61; 95% CI, 0.38-0.98) for early screeners. These findings remained consistent in the extended nonadherence adjustment model, with a 25% reduction in incidence (aRR, 0.75; 95% CI, 0.72-0.77) and a 34% reduction in mortality (aRR, 0.66; 95% CI, 0.62-0.71).

However, the researchers acknowledged some limitations. At the time early-age screening was implemented, age- and sex-specific FIT cutoff values had not yet been established, which may have influenced screening accuracy. Additionally, cultural, genetic, dietary, and health system differences may have affected how applicable the findings are to other populations.

Despite these limitations, the researchers believe these findings align with growing evidence supporting earlier screening and underscore the need for further international research to inform global guidelines.

“This study found that initiating FIT screening at age 40 to 49 years was associated with further reduction in CRC mortality and incidence compared with starting screening at age 50 years,” wrote the researchers. “These results provide strong empirical support for lowering the CRC screening age, with substantial public health implications.”

References

1. Chiu HM, Chen SL, Su CW, et al. Long-term effectiveness associated with fecal immunochemical testing for early-age screening. JAMA Oncol. 2025 Jun 12. doi: 10.1001/jamaoncol.2025.1433

2. Reese J. Contributor: An urgent call to action as colorectal cancer rates skyrocket among young people. AJMC^®. November 4, 2025. Accessed June 12, 2025. https://www.ajmc.com/view/contributor-an-urgent-call-to-action-as-colorectal-cancer-rates-skyrocket-among-young-people