多発早期胃癌―内視鏡治療の立場から―外科切除例多発早期胃癌も含めて

Multiple Early Gastric Cancer from the Standpoint of Endoscopic Therapy: With Analysis of Surgically Resected Multiple Early Gastric Cancer Cases

要旨　多発早期胃癌の頻度は外科切除例の11.4％，内視鏡的切除例(ER例)の10.4％であった．ER例では同時性多発早期胃癌4.8％，異時性多発早期胃癌5.6％であった．異時性病変発見までの期間はER後1年以上経過し発見された例が73.7％と高率で，ER後2年以内に約半数，5年以内に79.0％が発見されていた．ER後の経過年数が6年以上では内視鏡検査受診率は30％前後と低率で，他病死による死亡率も増加していた．外科切除例，ER例とも主・副病変の組織型はいずれも分化型，肉眼型では同一肉眼型が，存在部位ではM，A領域の同一区域あるいは隣接区域に高率であった．異時性多発病変のER例では大きさ11～20mmでの発見が21.1％を占め，1例が深達度sm₁で，10mm前後での発見努力が必要である．ER後外科切除例では2例の異時性進行癌の見逃し例があった．外科切除例での副病変の大きさは10mm以下が55.9％を占め，そのうち病理発見が70.2％と高率であり，ER後の経過観察では微小胃癌，小胃癌の存在に十分注意を払う必要がある．

　The incidence of multiple early gastric cancer was 11.4% of the surgically resected cases (SR) and 10.4% of the endoscopically resected cases (ER). Synchronous and metachronous multiple gastric cancers were detected in 4.8% and 5.6% of the ER respectively. The metachronous lesions that were found more than one year after the endoscopic resection occupied 73.7% of the total lesions. About half of the metachronous lesions were found within two years after endoscopic resection, and 79.0% of them were detected within five years after endoscopic resection. The endoscopic follow-up rate of the cases that had undergone endoscopic resection more than six years before was as low as 30% and the death rate excluding that of gastric cancer increased. In both SR and ER, most of the main and accessory lesions were both differentiated type, the same macroscopic type, and were located in the same area and/or adjacent area of M and A. Twenty-one percent of the metachronous multiple lesions were found 1 to 20 mm in size, however, one of them infiltrated the submucosal layer (sm₁). We need to make an effort to detect a lesion as small as 10 mm in size. There were two missed cases of metachronous advanced cancer in the ER followed by surgical resection. In the SR, 55.9% of the accessory lesions were found less than 10 mm in size, but 70.2% of them were detected by histological examination. These results suggest that we need to pay attention to find minute and small gastric cancers in the follow-up examination.