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.

In Japan, population-based colorectal cancer screening using the fecal immunochemical test was introduced in 1992. However, colorectal cancer mortality and incidence remain high, indicating that numerous challenges persist in colorectal cancer screening. One key issue is the urgent need to establish a nationwide data management system to elevate Japanese screening programs to the level of organized screening programs. To improve colorectal cancer screening in Japan, it is essential to base discussions on findings and data from Japanese research. Therefore, this paper discusses appropriate modalities for colorectal cancer screening based on Japanese research data. The fecal immunochemical test-based screening is a noninvasive and effective method; however, the data on its diagnostic accuracy and interval cancer suggest limitations, particularly in detecting right-sided colorectal neoplasia. To compensate for these limitations, further utilization of total colonoscopy warrants discussion. Screening with total colonoscopy is expected to be highly effective and cost-efficient; however, challenges remain in ensuring its acceptability and maintaining quality standards. Moving forward, it is desirable to establish an optimized screening framework that appropriately combines the fecal immunochemical test and total colonoscopy, with consideration to risk-stratified screening approaches.

The prognosis for invasive pancreatic cancer is extremely poor, and pancreatic cancer is well known as the most difficult type of cancer to treat. On the other hand, it has been reported in recent years that the prognosis improves dramatically if the tumor can be diagnosed at a small diameter, making early diagnosis essential to improving the prognosis of pancreatic cancer. In other words, the major challenge for the future is how to detect pancreatic cancer at an early stage, perform the necessary diagnostic examinations without excess or deficiency, and link the findings to treatment. The Pancreatic Cancer Early Diagnosis (Hi-PEACE) project launched throughout Hiroshima Prefecture in January 2023. The purpose of this project is 1) to detect early pancreatic cancer based on risk factors for pancreatic cancer and indirect findings from images, regardless of symptoms, and 2) to establish a smooth hospital collaboration between core facilities and clinics in each regional medical district throughout the prefecture. It is expected that such procedures throughout the prefecture will lead to earlier diagnosis of pancreatic cancer, a dramatic improvement in the prognosis of pancreatic cancer, and the establishment of new early diagnostic markers for pancreatic cancer.

Objective The purpose of this study was to evaluate the usefulness of the FIB-3 index to detect severe fibrosis and liver cirrhosis in nonalcoholic fatty liver disease (NAFLD) at health check-ups.

Methods We enrolled 791 patients with NAFLD among 2,704 health check-up cases to evaluate the usefulness of the FIB-3 index and compared it to the FIB-4 index. We also compared the two indices based on shear wave elastography (SWE).

Results Two hundred fifteen patients among 791 NAFLD patients (8.0% of all 2,704 cases) needed further examination with a FIB-4 index ≧1.3. However, only 13 patients among 791 NAFLD patients (0.5% of all 2,704 cases) needed further examination with the FIB-3 index (F3 and F4 cases in FIB-3 index). Based on SWE, the false-positive rate of the FIB-4 index was high and the false-negative rate of the FIB-3 index was high.

Conclusion Using the FIB-3 index to detect severe liver fibrosis and liver cirrhosis in patients with NAFLD (high-risk NAFLD) is useful.

Objective This study aimed to reveal the details of lesions diagnosed as gastric submucosal tumors using gastric radiography.

Subjects and Methods We studied 92 lesions diagnosed as gastric submucosal tumors out of 23,894 using optional gastric radiography at our hospital between April 2015 and August 2023. We retrospectively studied the tumor diameter by lesion site, imaging methods (double-contrast or thin-layer method), and final diagnosis.

Results The number of tumors in the U, M, and L regions was 53, 21, and 18, respectively. The overall mean tumor diameter was 15.6 ± 12.4 mm, showing no significant difference among lesion sites in the U, M, and L regions. The double-contrast method was more commonly used to visualize tumors in the U and L regions, whereas the thin-layer method was more commonly used to visualize tumors in the M region. Of the 53 lesions closely examined using endoscopy, 25 were actually submucosal tumors. In addition to submucosal tumors, one adenoma lesion and one early-stage cancer lesion were identified.

Conclusion The thin-layer method was useful for visualizing gastric submucosal tumors in the M region using gastric radiography. A wide range of tumors, including epithelial tumors, were identified.

Objective In Japan, the number of colorectal cancer-related deaths has increased, and one of the reasons for this is the low rate of persons who undergo colorectal cancer screening and a low rate of those who undergo detailed examination. On the other hand, shared decision-making (SDM) (by the patient and medical staff) to add total colonoscopy (TCS) or computed tomography (CT) colonography to a fecal occult blood test for colorectal cancer screening is performed in the United States, where the number of colorectal cancer-related deaths has slightly decreased. In this study, we examined whether SDM-based colorectal cancer screening is possible in Japan from the viewpoint of the processing capacities of TCS and CT colonography.

Subjects and Methods We investigated the implementability of occasional colorectal cancer screening via TCS or CT colonography at 50 years of age based on the number of TCS sessions and that of abdominal CT sessions performed using a ≥16-row multi-slice CT system that facilitates CT colonography.

Results SDM-based occasional colorectal cancer screening is difficult to manage using TCS alone, but it can be performed when CT colonography has increased processing capacity.

Conclusions It is possible to perform SDM-based occasional colorectal cancer screening with TCS and CT colonography as options. If this is realized, it may lead to a decrease in the number of colorectal cancer-related deaths.

Purpose The purpose of this study was to analyze the annual trends in colorectal cancer screening performance in Tottori Prefecture over the past 18 years, and to clarify the current status and problems.

Subjects and Methods We investigated the annual trends in the screening rates, recall rates, and detailed examination uptake rates, as well as the results of detailed examinations, for colorectal cancer screening in Tottori Prefecture over the 18-year period from 2004 to 2021, based on the Tottori Prefecture Cancer Screening Performance Report. The subjects were residents aged 40 years or older who did not have the opportunity to undergo screening at their workplace, etc., and were estimated using the calculation formula indicated by the Ministry of Health, Labour and Welfare.

Results The number of people who underwent screening (percentage of women) in 2004, 2013, and 2021 was 54,170 (62.8%), 55,556 (61.6%), and 53,884 (59.9%), respectively, and the screening rate was 31.1%, 29.2%, and 29.7%, respectively, showing no significant change. The recall rate also remained largely unchanged. On the other hand, the detailed examination uptake rate rose from 67.9% in 2004 to 76.4% in 2021 (p<0.00001), but it still did not reach 90%. The colorectal cancer detection rate (0.24-0.27%) and the rate of early-stage cancer (approximately 60%) were stable. Although there was no significant change in the rate of colorectal cancer detected in the detailed examinations (3.5-4.5%), the rate of colorectal adenoma significantly increased from 26.7% to 46.3% (p<0.00001).

Conclusions Over the past 18 years, the screening rate for colorectal cancer has remained flat, and the detailed examination uptake rate has not improved sufficiently. In the future, it will be necessary to consider new measures, such as the introduction of efficient endoscopic screening.