linitis plastica型胃癌診断の現状―集検受診群と病院例から

Present Situation of Diagnosis of Linitis Plastica Type Cancer of the Stomach

要旨　集検におけるlinitis plastica型癌（以下LP癌）の頻度は病院例に比べて低い．この一因としては，集検が無愁訴群を対象とし，受検間隔が年1回という制約条件下の検査であることが考えられる．逆追跡例の検討では大彎の軽度の辺縁陥凹を伴う限局性硬化，凹凸状硬化，レリーフの硬化など壁伸展障害に関するものが多かったが，1つの所見が単独にみられるというより，いくつかの所見が並存することがある．胃切除術後の長期生存例は5例であり，胃全体の伸展性がよい時期に診断すれば予後が期待できることが示唆された．

　1. Frequency of linitis plastica type cancer in mass survey examination of the stomach

　During the decade between 1965 and 1974 (the first survey), 767,184 subjects underwent a mass survey examination. During this period of time, 1,380 cases in all were found to be suffering from cancer of the stomach. This represented 0.18% of all subjects examined. Out of these there were 821 cases of advanced cancers. Among them, there were 30 cases of linitis plastica type cancer, which amounts to 2.17% of all stomach cancers, and 3.7% of all advanced cancers.

　Next, during the decade between 1975 and 1984 (second survey), there were 1,199,646 subjects examined, out of which 2,229 cases were found to have cancer of the stomach. This represented 0.186% of the total. Among them, 22 cases were linitis plastics type cancer, comprising 0.99% of all stomach cancers detected, and 2.4% of all advanced cancers.

　On the other hand, as far as clinical cases were concerned, during the decade between 1981 and 1990, there were 1,512 cases of operative cancer at this center, out of which 589 cases were advanced cancers. Among them, 54 cases were diagnosed as linitis plastica type cancer, which represents 3.6% of all stomach cancers detected, and 9.2% of advanced cancers. In conclusion, frequency of linitis plastica type cancer was higher in clinical cases than in cases found in mass survey examinations.

　2. The retrospective study of linitis plastica

　Among 48 cases which could be used for retrospective study, there were 27 cases with rigidity or irregularity such as the greater curvature, 13 cases with rigidity or enlargement of mucosal folds.

　3. Cases of linitis plastica type cancer which survived five years or more after gastrectomy

　Among the patients who underwent gastrectomy, there were five of them who have survived for five years or more. Although these patients were diagnosed to have impression images made by rigidity or irregularity such as the greater curvature, or enlargement or rigidity of mucosal folds, these images were more easily detected in a double contrast radiograph with less amount of air. However, a characteristic point was that wall compliance was maintained and the stomach became extended enough in a double contrast radiograph containing a great amount of air.