Colorectal Cancer Screening at Age 40: Reducing Death Risk by 40 Percent

Rising Colon Cancer in Younger People and a New Imperative

Colorectal cancer (CRC) is the world's third most common cancer and second leading cause of cancer death. Beyond these statistics, however, a deeper reality has alarmed clinicians and public health authorities: CRC is no longer solely a disease of older age. It is increasingly diagnosed even in people in their early 40s. Reports of a 500% increase over the past 20 years even among children aged 10-14 highlight the seriousness of this silent early-onset epidemic.

Traditional guidelines generally recommended colorectal cancer screening from age 50, more recently from 45. Over the past decade, however, an annual CRC incidence increase of approximately 3% among people aged 40-49 suggests this threshold may no longer offer enough protection. Younger patients also tend to present with more advanced, aggressive disease and fewer treatment opportunities. This has individual, social, and economic consequences because this age group is at the peak of workforce productivity and social contribution.

These concerns prompted a strong cohort study from Taiwan, published on June 12, 2025, in JAMA Oncology . Published in June 2025, it reignited debate: should colorectal cancer screening start at age 40? Its answer is not merely yes; it describes an urgent public health intervention.

🔹 Main Study Findings

• Study Population: In Taiwan, 263,125 individuals were studied.

• In the early-screening group (ages 40-49):

  • Each year, approximately 26 of every 100,000 people (26.1) were diagnosed with colorectal cancer between ages 40–49.

  • 3.2 of every 100,000 peopledied of colorectal cancer within this age range.

  • These rates show that early FIT screening is effective at detecting disease and can reduce the risk of death .

FIT (Fecal Immunochemical Test), detects occult blood in stool as a noninvasive screening test. To detect colorectal cancer or polyps early, it measures hemoglobin with high sensitivity in a small stool sample collected at home.

• In the group screened only from age 50 onward:

  • Each year, approximately 43 of every 100,000 people (42.6) were diagnosed with colorectal cancer among those aged 50 and older.

  • Each year, approximately 7.4 of every 100,000 peoplein this age group died of colorectal cancer.

  • These data show that beginning screening only after age 50 is associated with both more disease and higher mortality.

The difference indicates a meaningful protective effect from starting FIT at a relatively early age, such as 40.

🔹 Screening Effectiveness in Numbers

Propensity Score Matching (PSM) analyses produced the following effects:

• Propensity Score Matching (PSM) enables fair comparisons between groups. This analysis showed that people starting FIT screening at ages 40–49 had a 21% lower risk of colorectal cancer and a 39% lower risk of cancer death.

• These effects were obtained after balancing group differences that can occur in nonrandomized studies, suggesting that early screening is genuinely protective.

• Additionally, “nonadherence bias” and other biases were corrected in further analyses, which found that early screening reduced colorectal cancer risk by 25% and death risk by 34%. This shows that the findings were not simply chance and were confirmed across different statistical models.

📈 Cancer at a Young Age: A Real Threat

A 500% increase in colorectal cancer cases among children aged 10–14 has been reported over the past 20 years. Among those aged 40–49, incidence is increasing by approximately 3% annually.

These increases are associated with factors such as

• lifestyle changes,
  • obesity,
  • physical inactivity,
  • processed meat consumption,
  • refined/convenience foods, and
  • antibiotic use 

.

📊 What Do International Guidelines Say?

• USPSTF and ACS: Lowered the screening age to 45 (2021).

• Austria: Starts FIT screening at age 40.

• Türkiye: The national program still recommends screening the general population at ages 50–70.

These data provide a scientific basis for expanding FIT screening, particularly in the 40-49 age group.

💼 Clinical and Social Implications

• With FIT screening at ages 40–49, 1 CRC case can be prevented per 1548 screenings .

• The same result requires 2079 screenings in those aged 50 and older.

• With benefits for workforce productivity and early diagnosis, FIT's noninvasive, economical approach could become important in public health strategies.

✅ Conclusion: Is It Time to Lower the Screening Age?

Yes. More than 17 years of follow-up suggest starting FIT screening at age 40 is more effective than starting later. Each country's epidemiology, healthcare infrastructure, and economic capacity must be considered. However, particularly in at-risk groups and with greater public awareness, screening at 40 may become a new norm.