X-ray examination has been widely applied in gastric cancer screening all over Japan. However, on some small islands of the Okinawa Archipelago, this procedure has been impossible to carry out for technical reasons. Therefore, since 1981, the gastrointestinal department of the University of the Ryukyus Hospital has conducted endoscopic examinations in gastric cancer screenings in order to contribute to the health care of the residents of those islands and the epidemiological and clinical studies of gastric cancer mass screening.
We performed 7,082 endoscopic examinations for a total of 6,444 residents on 9 islands in gastric cancer mass screenings conducted from 1981 to 1989. During this period, we diagnosed 6 cases of esophageal cancer and 18 cases of early gastric cancer. Notably, in our work on Yonaguni Island, we diagnosed 7 cases of gastric cancer over a period of 5 years of endoscopic mass screenings, whereas no case of gastric cancer was identified within the subsequent 8 years of X-ray mass screenings.
Colorectal cancer mass screenings have been conducted in Japan since 1992, but they were not performed on the Yaeyama Islands until 1996 because of the insufficient supply of equipment and personnel required for colonoscopic examinations. Therefore, we performed thorough colonoscopic examinations for 180 examinees over the course of 5 weekends, and identified 23 cases of colorectal cancer, including 11 cases of early cancer.
These results clearly indicate that endoscopic examination in gastrointestinal cancer mass screenings has contributed to the health of the residents of a region where X-ray mass examination is not easily accessible. On the other hand, since the consultation rate for cancer mass screenings and detailed examinations is still low, improving the consultation rate is the most important nation-wide challenge today.

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Although Ota City had been conducting mass gastric cancer screenings by means of indirect fluororadiography as one of its public projects, the number of examinees continued to decrease every year since 1986, when the peak level was reached. In an attempt to reverse this trend, the Ota City Medical Association proposed the introduction of an additional program: namely, to conduct gastric cancer detection at individual clinics. This proposal was accepted by the city and has been put into practice since 1999.
The examination at individual clinics was provided in two ways, i.e., direct fluororadiography and endoscopy. Also, additional laboratory testing with serum pepsinogen examination was conducted as a reference. Thus, examinees could select one of three procedures, including the mass gastric cancer screening by means of indirect radiography. The total number of examinees for gastric cancer detection in 1998, prior to the introduction of the examination at individual clinics, was 6,409. After the new scheme was introduced, it continued to increase every year, and nine years later, in 2007, it reached 10,955. The total number of examinees in 2007 accounted for 17.3% of the population of Ota City. Out of the total number of examinees in 2007, those who selected the examination at individual clinics accounted for 83%. Out of all the examinees who visited individual clinics, those who selected the endoscopic examination accounted for 88%. The demographic data in 2007 showed that female examinees exceeded 60% of all the examinees for both the mass screening and the examination at individual clinics. The average age of the examinees who selected the examination at individual clinics was about 10 years higher, for both male and female examinees, than that of those who selected the mass screening. The percentage of gastric cancer detection was 0.23% with the mass screening, 0.20% with the direct fluororadiography and 0.61% with the endoscopy.
Out of 151 cases of gastric cancer detected, the positive results obtained by means of the serum pepsinogen test accounted for 75.5%, and the negative results accounted for 24.5%. From the viewpoint of cost effectiveness, defined as the cost per one case of detection of gastric cancer, the most cost-effective among the three methods of examination was the endoscopic examination (2.40 million yen), followed by the mass screening (3.45 million yen) and the direct fluororadiography (5.71 million yen). It is expected that the number of examinees who select the examination at individual clinics will increase further in the future. This suggests that high-quality research activities must be conducted in order to continuously provide citizens with sufficient data useful for the evaluation of the effectiveness of these detection methods and that many more medical sites and human resources must be secured as a top-priority task.

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A new radiographic method for gastric cancer mass surveying has been reported to be useful for gastric cancer screening and is currently being used in many medical facilities. However, there are many gaps in the quality of X-ray images between facilities, as well as between technicians. In an attempt to resolve this problem, we developed new criteria based on contrast effects for the visual evaluation of stomach X-ray images (grades A to E). A total of 60 cases (20 cases at each facility) with stomach X-ray images taken at three facilities participating in the Kagoshima Gastrointestinal Imaging Research Meeting were evaluated according to the criteria. The results were discussed by the members of the meeting. We found gaps in the quality of X-ray images between facilities. As for good images (grades A and B), we found differences in 45% of the results for the U area between facility 2 and facility 3. We also found differences in 45% of the results for the L area between facility 2 and facility 3. The main cause of the gaps was the difference between the radiographic methods used at those facilities. Evaluation of the grading of X-ray images and discussion between facilities are important for improving the techniques and the image quality.

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In order to evaluate the accuracy of endoscopic gastric examinations, out of 42 cases of gastric cancer detected by endoscopy during the period between September 2006 and August 2009, we selected 20 cases of gastric cancer lesions detected as “border-line false-negative” by repeat endoscopic examination at medical checkups, and studied their clinicopathodological characteristics as well as reviewed the records generated during the previous year. Regarding the macroscopic characteristics, all of the 20 lesions were of the early-stage depressed type (18 cases in 0-IIc, 1 in 0-IIb+Ic and 1 in 0-IIa+IIc). Regarding the histological characteristics, 12 lesions were differentiated (9 in tub1 and 3 in tub2), and 8 lesions were undifferentiated (5 in sig, 2 in por and 1 in muc). As for the maximum diameter of the cancerous lesions, 16 were 25 mm or smaller, whereas 4 were much larger than 25 mm (37 mm, 43 mm, 47 mm and 81 mm, respectively). As for the tumor stage, 17 cases were classified as pMpN0, and the 3 remaining cases were classified as pSM1pN0, pSM2pN0 and pMpN2, respectively. Our review of the records of the previous year revealed that there was no evident lesion in 5 cases (i.e., false-negative in a narrower sense), there was no mention of the location of the lesion in 4, there were evident lesions which were undetected in 8, and 3 cancerous cases had been diagnosed as non-cancerous by biopsy. Thus, since endoscopic examination sometimes produces false-negative results, it is important to recommend patients to undergo repeat endoscopic examination at medical checkups every year.

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Recently, esophagogastroduodenoscopy performed with an esophagogastroduodenoscope of small diameter (thin-EGD) for the detection of gastric cancer (GC) has become prevalent in opportunistic screenings. However, the efficacy of thin-EGD is still unclear. In the present study, we investigated the potency of thin-EGD for the detection of early GC. We analyzed the results of 14,075 endoscopic examinations performed at opportunistic screenings from April 2002 to March 2008 at our institution. Based on the endoscope models utilized in the GC screenings, the subjects were divided into two groups: the conventional endoscopy (CE) group and the thin-EGD group. There were no significant differences in the detection rate of GC (CE: 0.37%, thin-EGD, 0.20%) and early GC (CE: 86.7%, thin-EGD: 83.3%) between the two groups. However, in the subjects who underwent repeated screenings within a period of three years, the detection rate of intramucosal cancer for thin-EGD was significantly lower than that for CE (CE: 100%, thin-EGD: 62.5%). Furthermore, in six of 19 subjects (31.9%) who underwent repeated endoscopy, previous examinations revealed abnormal findings at the same location as that of the GC, suggesting a malignant lesion. In addition, at the previous examinations, all of these subjects were examined using thin-EGD. Thus, further studies are needed to clarify the efficacy of thin-EGD in the detection of intramucosal GC.

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The cancer screening rate in Yamagata Prefecture is high for Japan, but it is still too low to effectively reduce the rate of mortality due to cancer. Although various measures to improve the cancer screening rate are already in place, here we discuss several measures being implemented in Yamagata Prefecture and examine the direction of future strategies in cancer screening. We report success stories of patients who have benefited from early screening, and we introduce our newsletter on cancer-related issues and our efforts to work with public health centers to improve the cancer screening rate. We also report on the results of a cancer-related survey conducted at municipal government offices and corporations and suggest possibilities for future policies. Additionally, we discuss the importance of offering continued encouragement and support to individuals in the process of applying for cancer screening. Repeated recommendations to individuals who have not yet received cancer screening are also important.

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Aim: To review the latest computer-aided diagnostic tools and methods for the screening of colon cancer by CT colonography (CTC).
Subjects: We analyzed the CTC DICOM data of 9 patients with colorectal cancers or adenomas more than 10 mm in size. All of the lesions could not be detected by the Siemens Syngo Colonography Polyp Enhanced Viewing system (PEV-negative lesions). The 9 patients had 29 polyps more than 3 mm in size, which included 8 cancers. All patients underwent bowel preparation with isotonic magnesium citrate, and CTC examination in the prone and supine positions was performed using 1,400 - 2,000 ml of room air for bowel distention.
Method: The prone and supine data of 9 patients were analyzed using Colon VCAR (GE Healthcare, WI). We compared the findings of this analysis with the clinicopathological findings.
Result: In all patients, 8 small (<=5 mm), 11 medium (6-10 mm) and 10 large (>=10 mm) polyps were found during the optical colonoscopic examination or surgery. The results of the Colon VCAR analysis showed that, when the response threshold was set to 5 mm, 2 PEV-negative lesions were detected in the supine position and 3 in the prone; further, when the threshold was set to 3 mm, 7 PEV-negative lesions were detected in the supine position and all 9 in the prone. At the response threshold of 5 mm, the detection sensitivity for all 29 lesions was 27.6% in the supine position and 20.7% in the prone; further, at the threshold of 3 mm, the sensitivity was 75.6% in the supine position and 89.7% in the prone. At the threshold of 3 mm, the detection sensitivity for 27 of the 29 polyps in the prone or supine positions was 93.1%; however, at this setting, an average of 4.0 false-positive diagnoses were made per series in the supine position and 2.6 in the prone.
Conclusions: With adequate preparation, bowel distention and different positions, the sensitivity of Colon VCAR in detecting polyps more than 3 mm in diameter at the response threshold of 3 mm was over 90%. This sensitivity is sufficient to allow the use of this technique in interpreting the CTC data for colon cancer screening. In addition, fecal tagging agents and digital cleansing techniques can be used not only to reduce the rate of false-positive diagnoses, but also to facilitate the detection of polyps buried under watery stools.

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