Lowering the age for colorectal cancer screening

Colorectal cancer (CRC) remains a leading cause of cancer-related mortality worldwide, including in Taiwan, where early detection is crucial for improving outcomes. Recent studies reveal a rising incidence of early-onset colorectal cancer (EOCRC) in individuals under 50, promoting discussions about lowering the recommended age for CRC screening.^{1, 2} A study by Chang et al. highlights the adenoma detection rate (ADR) in screening colonoscopies among individuals aged 40–75, providing critical insights into the efficacy and implications of early screening.³

In Chang's study, the ADR for individuals aged 40–44 years, was 28.0%, compared to 41.5% for those aged 50 and older. Although younger populations showed a lower ADR in, their rates still exceed the current ADR benchmark of 25%, demonstrating the feasibility of initiating screenings earlier. ADR is strongly correlated with reduced CRC incidence and mortality.^{4, 5} The study's results emphasize the potential of detecting precancerous colon adenomas earlier, which could significantly impact CRC prevention strategies.

Historically, CRC screening began at age 50 for average-risk individuals among many countries. However, lifestyle factors such as high consumption of red and processed meats, low intake of fiber-rich foods like fruits and vegetables, physical inactivity, smoking, and rising obesity rates have contributed to the growing burden of CRC among younger populations.¹ EOCRC tends to be more aggressive and is often associated with poorer prognosis compared with CRC in older individuals.² The increasing prevalence of EOCRC has been noted recently. This alarming trend highlights the need to modify current screening guidelines. Early detection through screening colonoscopy could help address this incidence effectively.

Chang et al.'s study also identified gender differences in ADR, with males consistently exhibiting higher rates than females across all age groups.³ While the ADR for women aged 40–44 years was slightly below the 20% which is the female ADR benchmark, the overall ADR for younger populations remained robust, supporting the extension of screening to these age groups. One concern with lowering the screening age is the potential impact on the cost-effectiveness and efficiency of CRC screening programs. Chang et al. revealed a slight decrease in overall ADR when younger populations were included, as these groups typically exhibit fewer adenomas. However, the broader benefits of early detection outweigh this challenge. Targeted strategies, such as prioritizing individuals with a family history of CRC or other risk factors, could optimize resource allocation while maintaining high-quality care.^{6, 7}

The shift toward earlier CRC screening aligns with updated recommendations by the US Preventive Services Task Force, which lowered the starting age for CRC screening to 45 in 2021.⁸ Policymakers must weigh the benefits of early detection against the logistical challenges of expanding screening programs. Increased demand for manpower of colonoscopies may strain healthcare systems, particularly in resource-limited regions. Innovative approaches, such as integrating non-invasive stool-based tests with colonoscopy follow-ups, may alleviate these pressures while maintaining high detection rates.^9-11 Taiwan Colorectal Cancer Screening Program is a nationwide population-based fecal immunochemical testing (FIT) screening started in 2004, which is a biennial single-sample FIT screening for subjects aged 50–69 years.¹⁰ This large, prospective Taiwanese cohort undergoing population-based FIT screening for CRC had demonstrated a significant CRC mortality reduction.^{12, 13} However, the incidence of CRC still increased in those 50–54 years of age, likely due to the rising colon adenoma incidence in individuals aged 40–49. The prevalence of colon adenoma in those 40–54 years of age increased in the Taiwanese population.¹² These findings suggest a need to revise the screening age.

The rising incidence of EOCRC demands urgent action. Lowering the screening age to 40 for average-risk individuals could play a vital role in reversing this trend. Although Chang et al.'s study has limitations, including its single-center, retrospective design and reliance on health check-up populations, it provides compelling evidence that early screening is both effective and feasible. The findings raise important questions about whether screening programs should begin even earlier, particularly in high-risk populations.

Healthcare providers, policymakers, and public health experts must collaborate to address these epidemiological changes. By adapting screening programs to meet the needs of younger populations, we can reduce the burden of CRC and save countless lives. The time to act might be now.

The author declares no conflicts of interest.