Abdominal ultrasonic cancer screening is widely performed during health checkups, etc., but the quality is not sufficiently controlled. In April 2014, the Japanese Society of Gastrointestinal Cancer Screening, the Japanese Society of Ultrasonics in Medicine, and the Japanese Society of Ningen Dock jointly published the "Manual for abdominal Ultrasound in Cancer Screening and Health Checkups." From 2014 (H26) to 2018 (H30), the annual report of Gastrointestinal Cancer Screening in Japan has been compiled based on the manual. Although the ultrasonic equipment and functions of Color Doppler, etc. satisfy the standards, differences in the duration of scanning operation and the number of recorded images between facilities were found. On the other hand, after the introduction of the manual, the cancer detection rate improved, with the highest cancer detection from category 4, followed by detection from categories 3 and 5, and almost no cancer detection from categories 0, 1, and 2. The most common cancers found by abdominal ultrasonic cancer screening were stage I, and more than 60% were treated by resection. However, there are many cases of unknown categories, and it is necessary to further disseminate the manual.

Therefore, based on the results of the questionnaire survey on the revision of this manual and the annual report of Gastrointestinal Cancer Screening in Japan, this manual was revised. It is hoped that the effectiveness of cancer screening can be evaluated by further disseminating the revised version of the "Manual for abdominal Ultrasound in Cancer Screening and Health Checkups (2021) ", and conducting high-quality abdominal ultrasonography.

Purpose: This study aimed to clarify the characteristics of gastric cancer detected years after Helicobacter pylori (H. pylori) eradication therapy and determine the surveillance period required following H. pylori eradication, focusing on post-eradication gastric cancer detected by gastric endoscopy screening.

Subjects and methods: Among 289 gastric cancers detected from April 2009 to October 2019, 45 after H. pylori eradication (44 early-stage cancers and one advanced cancer) were included in the study. Annual trends in the detection rate of gastric cancer after H. pylori eradication were investigated, and clinicopathological findings were evaluated. In addition, clinicopathological characteristics between gastric cancers detected within 5 years and more than 10 years following H. pylori eradication were compared.

Results: The detection rate of gastric cancer after H. pylori eradication gradually increased each year, accounting for 34.2% of all gastric cancers detected in the past 4 years. The majority of the patients were male, and the types of cancer were mainly depressed (0-IIc) and differentiated, occurring in the middle and lower regions of the stomach. Thirty (66.7%) cases of gastric cancer detected within 5 years of H. pylori eradication showed moderate to severe mucosal atrophy. The incidence of differentiated-type cancers is high. In contrast, nine (20.0%) cases of gastric cancer detected more than 10 years after H. pylori eradication showed mild to moderate mucosal atrophy, and undifferentiated lesions accounted for more than half of the cases (five of the nine [55.6%] cases).

Conclusion: More than 10 years after H. pylori eradication, 20% of patients were detected with gastric cancers, indicating that continuous long-term monitoring after H. pylori eradication is necessary. Further, the frequency of detecting undifferentiated carcinoma increased against a background of mild to moderate gastric mucosal atrophy.

In recent years, Saga Prefecture, which has many gastric cancer patients, has been actively engaged in gastric cancer screening and countermeasures regarding preventing this disease in each age group, from children and young adults to the middle-aged and elderly. As primary prevention, we carried out the "Gastric Cancer Countermeasure Promotion Project for the Future" that, from 2016, entitles all 15-year-olds in the prefecture to Helicobacter pylori (H. pylori) infection testing and eradication at public expense. In the three years from 2016, 21,368 people have participated and the project is ongoing. Next, in the young adult group, H. pylori examination assistance is provided in 13 out of 20 municipalities in the prefecture, which may have an important effect on preventing gastric cancer by H. pylori eradication. For middle-aged and older people, in addition to the conventional gastric barium examination, we introduced gastro endoscopy as an organized screening in 2017 in Saga prefecture. Targeting even-numbered age people in their 50s and 60s, the number of registered facilities is 17 (2017), 53 (2018), 73 (2019), and 92 (2020) with corresponding examinee numbers being 82, 544, 797, and 948, respectively, from 2017 to 2020. Six gastric cancers were found in the last four years. In 2020, all 20 municipalities in Saga prefecture participated. In the future, it is important to further increase the number of examinees. Additionally, from 2018, "The Cancer Eradication Special Measures Office" was established in the Health Promotion Division of the Saga Prefecture Health and Welfare Department. With these efforts, we believe that this comprehensive H. pylori screening and eradication campaign will have a lasting impact on the prevalence of gastric cancer in the Saga Prefecture.