This report is biased on 1,139 patients with gastric cancer (GC) detected by mass screening conducted by the Center for Adult Diseases, Osaka during 1961-1985. Early GC totalled 527 patients and advanced GC totalled 6121 patients. In 859 patients curative resection was performed. Their vital status was traced yearly and six patients were lost to follow-up. Relative survival rates of screening-detected GC patients were 69-70% and almost constant after 5 years from operation/diagnosis. The survival curve in which only death from GC was counted as a death was almost equal to the relative survival curve in its shape and value. The hazard rates of screening detected GC patients decreased rapidly within 7 years and remained low affter 7 years. It was confirmed by this long-term follow-up study that about two thirds of GC patients detected by screening were successfully cured of their disease. Cancer 63:613-617, 1989. N JAPAN mass screening for stomach cancer has been I carried out for over 25 years mainly with photofluo-rographic radiography, and 5.2 million people were examined in 1985. The main purpose of this screening is to detect as many curable gastric cancers (GC) as possible in the asymptomatic phase:, and to reduce the number of deaths from GC. In order to evaluate this screening program , it is necessary to follow up the detected GC patients for a long period and to know their prognosis. At the Department of Mass Examination for Stomach Cancer in the Center for .4dult Diseases, Osaka, yearly followup surveys on all screening-detected patients have been carried out and the causes of death have been investigated for dead patients. Based on the results of this survey we calculated the survival rate of GC for a 15-year period, and analyzed the causes of death by years froh operation/diagnosis. Materials and Methods The subjects of our follow-up study were a total of 1,139 GC patients detected by mass screening conducted by the Department of Mass Screening of the Center for Adult Diseases, Osaka during 196 1 to 1985. Two hundred twenty patients were detected by the examination in the detection clinic of the Center with roentgenogram taken on a full size film, and the other 919 patients were examined in automobile units mounted with the x-ray apparatus where photofluorogram was taken on a 100 mm width roll film. Table 1 shows the sex and age distribution of our study subjects which consisted of 826 men and 313 women. The major age groups of detected patients were forties, fifties, and sixties. Table 2 shows the number of study subjects by cancer type and by method of treatment. Early GC totalled 527 cases. According to the classification of the Japanese En-doscopy Society, early GC is gastric cancer, the infiltration of which is limited to the mucosa or submucosa. The majority of the early GC in Table 2, i.e., 509 cases out of 527 were confirmed as early GC by examining resected stomach. For the remaining 18 patients, however, operation had not been conducted because either they refused it or they had other diseas...

To elucidate the natural history of colorectal polyps and to observe the influence of endoscopic polypectomy on the incidence of colorectal cancer, we conducted a retrospective cohort study of all patients who had undergone colonoscopic examination at the Center for Adult Diseases, Osaka, between April 1974 and December 1985. The study subjects consisted of a control group (760 non-polyp patients) and a polyp group (648 polyp patients, including 136 treated by polypectomy at the initial examination). These subjects were followed up until the end of 1987 by record linkage with the Osaka Cancer Registry's file to observe the occurrence of colorectal cancer. The O/E (observed/expected numbers derived from the general population) was 5.1 (95% confidence interval = 2.5-9.4) and 1.0 (0.1-3.6) for the polyp and control group, respectively. When subjects in the polyp group were categorized into polypectomy and non-polypectomy sub-groups, the O/E was 2.3 (0.1-12.6) and 8.0 (3.4-15.8) respectively. The relative risk of undergoing polypectomy to developing subsequent cancer was estimated at 0.3 (0.1-2.1). These results suggest an increased risk of developing cancer among polyp patients and the possibility of prophylactic effect of polypectomy against subsequent cancer. A large-scale and long-term follow-up study is required to confirm these findings.

To assess the validity of mass screening tests for gastric cancer conducted with three types of radiographic techniques, i.e., photofluorography by a mirror camera, photofluorography by an image intensifier, and direct radiography, 105,122 persons who underwent a total of 272,667 screening tests during 1970 through 1982 were followed through December 31, 1983 by means of a record linkage to the Osaka Cancer Registry, Osaka, Japan. The results of 1 year's follow-up from screening were defined as the gold standard and test performance values were calculated. Sensitivity of screening with photofluorography by a mirror camera, photofluorography by an image intensifier, and direct radiography was 90%, 8970, and 91%, and specificity was 86%, 92%, and 91%, respectively. The receiver operating characteristics curve for screening with photofluorography by an image intensifier resembled that for direct radiography and these two curves were located somewhat to the left of the curve for screening with photofluorography by a mirror camera. The authors conclude that the validity of screening with photofluorography by an image intensifier is almost equivalent to that of screening with direct radiography and both are superior to that of screening with photofluorography by a mirror camera.

In order to estimate the diagnostic validity of chemical fecal occult blood tests, i.e. orthotolidine (Shionogi A) and guajac (Shionogi B) slides for detecting cancers of the esophagus, stomach and colorectum, the authors followed up all the examinees (n=3,449) of comprehensive medical check‐ups at the Center for Adult Diseases, Osaka, by means of record linkage to the Osaka Cancer Registry's files. Then, diagnostic validity was calculated based on the results of two years’ follow‐up. Sensitivity for the respective cancers was 20.0%, 11.8% and 62.5% for Shionogi A, and 20.0%, 5.9% and 43.8% for Shionogi B slides. Likelihood ratio for the respective cancers was 1.4, 0.8 and 4.5 for Shionogi A, and 3.3, 1.0 and 7.5 for Shionogi B. Specificity was analogous among the three cancer sites, being 86% for Shionogi A and 94% for Shionogi B. These results suggest that the diagnostic validity of chemical occult blood tests for detecting cancers of the esophagus and the stomach is very poor, and therefore imply that close examinations of these sites for screening positives is unnecessary in mass screenings for colorectal cancer.

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