2026 Volume 64 Issue 2 Pages 122-129
Colorectal cancer is one of the leading causes of cancer incidence and mortality worldwide, and early detection and treatment through organized, population-based screening programs are of critical importance for public health. In recent years, accumulating evidence from randomized controlled trials (RCTs) and meta-analyses—particularly from Western countries—has clearly demonstrated that repeated use of the fecal immunochemical test (FIT), combined with programmatic management that links screening to diagnostic evaluation and treatment, effectively reduces colorectal cancer mortality. Consequently, organized screening programs with strict quality assurance have been increasingly implemented, and optimization of screening strategies, including lowering the starting age for screening, has been actively pursued.
While colonoscopy provides substantial individual-level risk reduction through the detection and removal of precancerous lesions, several challenges remain regarding its use as a primary population-based screening modality. These include its invasiveness, the risk of procedure-related complications, and limitations in medical resources such as trained endoscopists and facility capacity. As a result, colonoscopy-based screening has not been uniformly adopted as a population-wide strategy, despite its high diagnostic and preventive efficacy.
In Japan, a nationwide colorectal cancer screening program based on annual FIT has been established and has achieved considerable success. Nevertheless, several unresolved issues persist, including disparities in screening implementation among municipalities, variability in adherence to follow-up diagnostic colonoscopy after a positive FIT result, and insufficient strategies to address the increasing incidence of early-onset colorectal cancer in younger populations.
Looking forward, the integration of emerging technologies into existing screening frameworks represents a promising direction. Liquid-based molecular diagnostics, such as assays targeting tumor-derived DNA or RNA in blood or stool, as well as analyses of the gut microbiome and fecal metabolome, have shown potential to complement FIT-based screening. Rather than replacing established systems, these novel approaches may serve as adjunctive tools to enhance risk stratification, improve screening efficiency, and enable more personalized screening strategies. Incorporating such technologies into FIT-centered programs may facilitate the development of a more effective and sustainable colorectal cancer screening strategy tailored to the Japanese healthcare system.
