[in Japanese]

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[in Japanese]

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The purpose of the present study was to point out the problems of urinary Helicobacter pylori (Hp) antibody testing and serum pepsinogens (PG) testing for gastric cancer mass screening programs which include many senile subjects. A total of 295 gastric cancer patients (mean age 65.2±8.7 years) whose cancers were detected by gastroroentgenography during mass screening, were examined using both the quantitative immunoblot test for urinary Hp antibody and the serological PG level (the positive detection ; PG I<=70ng/ml and PG I/II<=3.0). The positive rate for PG, urinary Hp antibody and their combination was 70.7, 78.9 and 93.2%, respectively. The Hp+/PG- group, which showed low levels of gastric mucosal atrophy, contained an increasing number of younger subjects, poorly differentiated types and advanced-stage gastric cancers as compared with the other groups. The Hp+/PG+ and Hp-/PG+ groups were advanced in age and were mainly composed of well-differentiated types and early-stage cancers. The double negative Hp-/PG- group accounted for 6.8% of the gastric cancers. The majority of Hp-/PG- cases belonged to the aged generation but showed low levels of gastritis and atrophy. The combination of urine Hp antibody testing and serum PG testing seemed effective for gastric cancer screening. However, the occurrence of false negative cases for both tests is still problematic; therefore, the introduction of a highly sensitive Hp infection test and careful judgment of the serum PG test would be required for the achievement of efficient gastric cancer mass screening.

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In order to clarify the usefulness of gastric mass surveys conducted using a new standard method, we compared the data obtained from surveys conducted using the new standard method during the past two years with another set of data, which were obtained from surveys conducted using the conventional method during the two-year period prior to the transfer to the new method, from the standpoint of examination accuracy. The total number of subjects who underwent examination with the new method was 25,796. The percentage of individuals for whom further examinations were required, the detection rate of cancers and the hitting ratio of positive reactions with the new standard method were 10.1%, 0.116% and 1.14%, respectively. On the other hand, the total number of subjects who underwent examination with the conventional method was 26,488, and the percentage of individuals for whom further examinations were required, the detection rate of cancers and the hitting ratio of positive reactions with the conventional method were 9.5%, 0.094% and 0.98%, respectively. The new standard method (65%) was superior to the conventional method (61%) in terms of the cancer detection rate. We attempted to check whether there is any advantage in the degree of certainty regarding the percentage of examinations which yielded evidence and regarding the benign/malignant rate, and we observed an increase with the new standard method in the rate of examinations which yielded affirmative evidence. The detection rate for gastric cancers found in the fornix and antrum areas of the stomach was better with the new standard method than with the conventional one, probably due to the excellent depiction of the gastric mucosa. Also, with the new standard method, an increase was observed in the rate of checking of the anterior wall area of the stomach and in the detection rate of cancers in the areas of the anterior wall and the posterior wall.
In conclusion, these findings suggest that the new standard method has demonstrated its usefulness and that it can enhance the examination accuracy of gastric mass surveys.

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The immunological fecal occult blood test has been recognized as an effective tool for detecting colorectal cancers, but one of its shortcomings is that false negative findings are inevitable. We examined the false negative cases among the 212 cases of colorectal cancer detected among the 177,887 examinees for whom an immunological fecal occult blood test was carried out at our institute. False negative cases were found to account for 36.3% of the colorectal cancer cases, and 25% of those were advanced cancers. The fecal occult blood quantitative values were significantly lower in the false negative group (FN group) compared to the group that had been positive in the previous test (PP group) and the group that had been found positive in the first test (FP group). Considering that 73.9% of the cases were type 0, 69.2% had lesions 2 cm or less in size and the rate of intramucosal cancer was 54.5%, the false negative findings seemed to be related to the fact that the lesions were detected at early stages in more cases of the FN group compared to the other two groups. The rate of Dukes A in the FN group was about 80%, and endoscopic treatment was selected for 61.3% of the cases. Half of the advanced cancers in the FN group, however, were detected in the right colon, which reconfirmed the shortcoming of the immunological fecal occult blood test in detecting lesions in the right colon. The high rate of false negative results for colon cancer detection is a problem with this test, especially for the detection of cancer in the right colon. It seems essential for colorectal cancer mass screenings that health care professionals have a good understanding of the immunological fecal occult blood test, endeavor to increase its rate of application, and encourage people to have the test annually.

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