内視鏡による食道表在癌の深達度診断の精度

Diagnostic Accuracy of Endoscopy in Estimating the Depth of Invasion of Superficial Esophageal Carcinoma

要旨　食道表在癌の深達度を術前に正確に診断することは，治療方針を決定するうえで重要である．現在では色素法，拡大法を含めて内視鏡による診断が最も正確で普遍性があり有用と考える．ep・mm・sm癌の内視鏡所見を示し，深達度診断上の注意点につき述べた．143例の食道表在癌のうち切除標本の病理学的検索で深達度の判明している118例では，正診98例83.1％，深く読みすぎたもの11例9.3％，浅く読みすぎたもの9例7.6％であった．問題となるのはmmと診断してsmだった5例4.2％であったが，いずれも微小なsm浸潤（sm₁）であり，予後も良好であった．microscopicな浸潤は読みにくく，3cm以上のmm癌はsm₁である可能性が高く，白色調の隆起は見た目より浅い．内視鏡による深達度診断は満足しうるものと思われる．

　It is very important to precisely estimate the depth of invasion of superficial esophageal carcinoma so as to select proper operative procedure. So far, such techniques as chromoendoscopy and magnifying endoscopic observation are considered useful for that purpose. In this paper, we present endoscopic findings obtained in the cases with intraepithelial carcinoma, carcinoma limited to the proper mucosal layer (mm carcinomas), or microscopically invading carcinoma to the submucosal layer (sm carcinomas). And discussion was made on the crucial points in this diagnostic procedures.

　Among 143 cases of superficial esophageal carcinoma treated so far in our hospital, 118 cases were histologically examined regarding the depth of invasion and thus analysed. Accurate diagnosis was made in 92 patients (83.1%), overdiagnosis in 11 cases (9.3%) and underestimation in 9 cases (7.6%). Although 5 cases of histologically sm carcinoma were preoperatively underestimated as mm carcinomas, invasion to the submucosal layer was minimal (sm₁) and resulted in good prognosis. Since microscopic invasion was rather difficult to diagnose, it was not infrequent that a tumor of 3 cm in size or more pathologically proved to sm₁ carcinoma after endoscopic diagnosis of mm carcinoma. On the other hand, a whitish elevated lesion tended to be overestimated. Taken together, our endoscopic estimations of the depth of invasion as shown here were acceptable in selecting operative procedures.