In order to reduce cancer mortality, the cancer screening should be implemented with scientifically effective tests under a high level of accuracy control. There are differences in accuracy levels among screening institutions, so that harms may exceed benefits when poor-quality cancer screening is performed. It is obvious that the accuracy of screening tests is improved when accuracy control measures are enforced. Therefore, accuracy control measures are indispensable, even when endoscopic screening for stomach cancer is implemented.
When harms cannot be ignored, the screening test may not be recommended as a population based screening, even if it has been proven to decrease the chance of death from the cancer. Harms include false positive results, false negative results, over-diagnosis and accidental complications due to screening tests. It is possible that screening tests showing high detection rates of the cancer may have risks of over-diagnosis.
A call-recall system is useful to increase cancer screening, but a setup of target age is necessary for the efficient execution of this system. Practical and evidence-based cancer screening for the stomach is defined as effective cancer screening implemented for suitable age-targets under a high level of accuracy control.

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We defined cases of gastric cancer detected in patients annually undergoing screening as false negative and evaluated them by the following points: clinic-pathological findings, causes of false negative cases, years of gastroendoscopic experience of physicians, sites of lesions and false negative rates. All cases were in the early stage and 9 of these cases (52.9%) were completely treated by endoscopy. Eleven cases (64.7%) could have been detected by technical improvement of the endoscopist and more careful double check. Although the number of gastroendoscopies per year in our hospital is 3000, the false negative rate was 31.5% when all cases of gastric cancer detected in patients annually undergoing screening were defined as false negative. But when false negative cases were defined as those in which the lesions could be confirmed by the review of images in the previous year, the false negative rate was 14.8%. This result was almost the same as those of the so-called high volume centers. Therefore, it is possible to maintain high quality mass screening by endoscopy even in local cities by performing proper quality control.

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The colorectal cancer screening rate in Yamagata prefecture is highest in Japan and the detailed examination rate in Yamagata is 68.3% (fiscal 2011). These are still too low to effectively reduce the mortality due to colorectal cancer. Several measures (offers of a free coupon ticket for colorectal cancer screening, distribution of the fecal occult blood test kits, and others by some municipalities) have been implemented to increase the screening rate for colorectal cancer in Yamagata. The screening rate increased gradually from 30% in fiscal 2004 to 35.6% in fiscal 2011. Various measures (distribution of a leaflet that recommends a detailed examination and others) have been implemented to increase the detailed examination rate for colorectal cancer in Yamagata. But the total detailed examination rate in Yamagata has not been obviously improved. The most effective method is timely recommendations to individuals by phone or in person. We report the current trends and issues for colorectal cancer screening in Yamagata prefecture.

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We studied 1103 cases with a positive immunochemical fecal occult blood test undergoing total colonoscopy at our hospital (Itabashi Chuo Hospital) during the period from January 2011 through December 2012. At first, we divided our subjects into two groups: the group less than 65 years of age and the group 65 years of age or older and compared them regarding the following aspects: the number and size of the polyps, detection rate and location of colorectal cancer and early cancer ratio, and location of colorectal adenoma. We also made the same comparisons between genders. With regard to the location of colorectal cancer and adenoma, we compared between the right (including the cecum, ascending and transverse colon) and left colon (including descending and sigmoid colon and rectum). As a result, we found that there were significantly larger and more multiple polyps were in the elderly. We also found the detection rates both of colorectal cancer and of adenoma in the right colon were significantly higher in the elderly. There was a significant difference in the early cancer ratio between the age groups, with the advanced cancer being more prevalent in the elderly. With regard to gender, we found there were more multiple polyps in males. There were no significant differences concerning the other aspects between genders. With the findings of a higher prevalence both of cancer and of adenoma in the right colon in the elderly, it is extremely important to complete TCS in the elderly with a positive immunochemical fecal occult blood test, to reduce the morbidity and mortality of colorectal cancer.

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The patient was a 59-year-old woman. She underwent US screening during a mass examination, and a massive lesion was detected in the hepatic hilum. She was referred to our hospital.
US revealed a hyperechoic tumor 10mm in diameter in the left hepatic duct, but there was no dilatation of the intrahepatic duct. Computed tomography (CT) revealed bile duct wall thickening in the same position. EUS depicted a relatively homogeneous high echoic papillary tumor lesion, while retaining the external high echoic layer. Hence, we diagnosed a papillary tumor localized in the bile duct. Peroral cholangioscopy (POCS) shows the papillary tumor in the left hepatic duct, and the biopsy revealed hyperplasia epithelium. As the possibility of adenoma-carcinoma in situ could not be ruled out, the patient underwent left lobe, caudate lobe hepatectomy and extrahepatic bile duct resection. Pathological findings finally revealed a diagnosis of gastric type IPNB with adenoma.

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A 76-year-old man consulted our hospital for further examination of a protruding gastric lesion that had been detected in the upper gastrointestinal series. Esophagogastroduodenoscopy revealed extrinsic compression of the posterior wall of the gastric body. US demonstrated a cystic lesion with an irregularly thickened capsule, in which flow signal was detected by Doppler image. The capsule of the tumor showed almost the same staining pattern as the surrounding pancreatic parenchyma in contrast enhanced CT. Endoscopic ultrasound delineated the irregular capsule of the tumor and revealed a swollen regional lymph node. Laboratory findings, including tumor markers and hormonal data, showed normal findings. Distal pancreatectomy with splenectomy was performed based on a preoperative diagnosis of pancreatic neuroendocrine tumor as cystic degeneration with regional lymph node metastasis. The tumor was 40 mm in size, well demarcated, and solid with cystic degeneration. As tumor cells were immunohistochemically positive for chromogranin A and synaptophysin, the lesion was diagnosed as a pancreatic neuroendocrine tumor. An irregularly thickened capsule and abundant vascularity are useful findings to differentiate neuroendocrine tumors with cystic degeneration from other ordinary cystic lesions.

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