EMR適応早期胃癌における診断の実態と問題点―X線の立場から

The Present State of Radiological Efficacy in Diagnosing EMR-indicated Early Gastric Cancer and Cruxes Involved

要旨　術前にX線，内視鏡の両検査が行われ，切除標本の病理組織学的検査が済んでいる早期胃癌278例296病変を対象に，EMR適応・非適応の決定におけるX線診断の有用性の実態を分析し，以下のような結果が得られた．①EMR適応早期胃癌102病変(m：101病変，sm₁：1病変)に対してX線は94病変，92.2％を適応と診断しえていたが，内視鏡の96病変，94.1％にはやや及ばなかった．しかし，②非適応sm癌107病変(sm₁：29病変，sm_{2, 3}：78病変)を適応病変と誤診した症例は内視鏡の15病変，14.0％に対してX線は7病変，6.5％であり，X線のほうが勝っていた．特にsm_{2, 3}病変では内視鏡が11病変，14.1％を適応と誤診していたのに対して，X線は3病変，3.8％にとどまった．以上からX線診断は早期胃癌のEMR適応に関して，適応よりも非適応の決定により重要な役割を果たしていた．

　Analysing the present state of radiology to determine whether a lesion is to be treated by EMR (endoscopic mucosal resection). The study is based on early gastric cancers (278 cases, 296 lesions) where both pre-operative x-ray and endoscopic examination had been carried out and histological examination on resected specimens had been completed. We came to the following conclusions.

　1) On the basis of 102 lesions of early gastric cancer (m: 101, sm: 1), for which EMR was indicated, 94 lesions (92.2％) were correctly diagnosed as so indicated by x-ray. This detection rate was slightly inferior to endoscopy (96 lesions, 94.1％).

　2) However, on the basis of sm cancers not indicated for EMR (sm₁: 29 lesions), only 7 lesions (6.5％) were misdiagnosed by x-ray as indicated for EMR, while 15 lesions (14.0％) were misdiagnosed by endoscopy. In other words, x-ray was superior to endoscopy in the respect. In the case of 78 sm₂ lesions, while endoscopy misdiagnosed as many as 11 lesions (14.1％) as indicated for EMR, x-ray misdiagnosed only 3.8％ (3 lesions).

　Accordingly, pertaining to the decision of EMR indication in early gastric cancer, x-ray diagnosis was more accurate in diagnosing lesions as not indicated for EMR, than in diagnosing those lesions for which EMR was indicated.