pm胃癌の病理―早期胃癌と進行胃癌との関連性

Pathology of pm Gastric Cancer: Relationship between early and advanced cancers

　過去十数年間における胃癌の早期発見早期治療の目覚ましい進歩により，早期胃癌はもちろんのこと比較的初期の進行胃癌も相当多数集積されてきた．これらの資料によって，病理学的に多くの新しい知見，とくに胃癌の組織発生ならびにその進展と蔓延についての研究成果が得られた．病理材料からみてpm胃癌は初期の進行胃癌であり，胃癌の発生進展および蔓延過程の一断面であることは疑いのない事実である．また臨床的にみても術後5年生存率は早期胃癌と進行胃癌の中間に位置するものである¹⁾²⁾．しかし形態学的にみた早期胃癌と進行胃癌との間には多少の断絶がいまだに残っている．たとえばある1つの進行胃癌を見たときに，それがいかなる早期癌の型から由来したものかについては，なお推測の域を脱しない面がある．静的な病理材料からのみこれらの点について解明することは，おのずから限界があり，臨床的逆追跡資料を解析することが重要であると強調されている³⁾．

　いずれにせよ現時点でpm胃癌とはいかなるものであるか臨床病理学的に把握しておくことは重要なことであると思われる．

　Clinicopathological study was made in 221 cases of the gastric carcinoma, the invasion of which was limited to the muscularis propriae (pm) by dividing them into a group accompanied with ulcer formation (Ul+) and another without ulcer (Ul-). The following results were obtained

　1. The incidence of pm cancer was 9.1 per cent in 2,441 cases of gastric cancer submitted for resection. This percentage was smaller than that of m or sm cancer. The group with ulcer formation was more numerous (65.4%).

　2. The average age was 56 years. That of Ul (+) group was 55.1 years, and in Ul (-) group, 59.2 years. The male outnumbered the female with a ratio of 2.4 : 1, nearly the same as in early cancer.

　3. Incidence of pm cancer according to macroscopic classifications : The type simulating early cancer was of higher percentage (54.6%) than the Borrmann variety (42.1%). In the latter, the IIc type was most frequent (23.4%). In the type mimicking early cancer the highest percentage was seen in IIc-like pm cancer (25.9%).

　4. Incidence of pm cancer according to histological classification division: In the group of Ul (+), mucocellular adenocarcinoma was most frequent (35%), followed in the order of frequency by poorly differentiated type and well differentiated one. In the group of Ul (-), papillotubular adenocarcinoma and well differentiated tubular adenocarcinoma were most often seen.

　5. Incidence of pm cancer seen from the types of cancer invasion : The most frequent type was nodular (48.8%). Diffuse infiltrating variety was least often seen (17.9%).

　6. Prognosis of pm cancer: The 5-year-survival rate was 70.1 per cent, close to that of early cancer. In Borrmann type it was less favorable (63.2%). Seen from the patterns of infiltration, the tubular type offered poorer prognosis (65.9%).

　7. Special features of pm cancer: As far as we have been able to make out, our studied cases were a mere collection of cases having features more or less common to early and advanced cancers. In order to clarify the intermediate step between them, we ought to study in details of yet a greater number of pm cancer of the stomach.