食道粘膜下層癌の臨床診断

Clinical Diagnosis of Early Esophageal Cancer with Submucosal Involvement

要旨　当センターで切除した食道sm癌92例の脈管侵襲，リンパ節転移の有無に関し病理所見，臨床像を検討した．（1）切除標本の検討では，sm癌の70％に既に脈管侵襲を認め，そのうち45％がn（＋）であった．1cm前後の大きさで，表層平坦型，隆起成分の少ない表在隆起型ではリンパ節転移は少ない．また，小範囲のieを伴う複合型が，全く伴わない単純型や，広範囲にieのみられる複合型（すなわち表層拡大型）に比べてn（－）である頻度が高い．組織型では分化傾向を示す扁平上皮癌，特に高分化型で早期癌の頻度が高い．（2）n（＋）sm癌は大部分2群以上の遠隔リンパ節に跳躍型の転移を起こしており，n（－）sm癌の累積5年生存率85％に比べ，n（＋）では29％と極端に悪い．（3）表在癌のX線診断では，表在平坦型と亜有茎性腫瘤では早期癌の可能性が高い．その他の型では型分類のみでは転移の有無は判定できないが，個々の病巣の不整像，随伴病変の有無およびその性状を参考にすれば，〔ly，V〕と〔n〕はある程度予測できる．（4）表在癌の深達度は内視鏡の病型と密接な関係があり，sm癌は表在隆起型，潰瘍型が大部分であり，びらん型の一部が含まれる．隆起型とびらん型より成る“混合型”は，規約にはないが，sm癌の中でも脈管侵襲の頻度が高く，予後不良の型である．

　Among 92 cases of esophageal cancer with submucosal involvement (including 18 cases of R-superficial cancer) which were resected at our Institute of Gastroenterology, pathological findings regarding vessel invasion and lymph node metastasis, clinical features, x-ray findings and endoscopic diagnosis were studied. The results obtained were as follows:

　1) Resected specimen of sm cancer except for R-sm carcinoma showed that 70% of them already had vessel invasion and 45% of them had n (+). The sm cancer which had less lymph node metastasis showed the following characteristics. Namely, their sizes were around 1 cm and their macroscopic types were flat type which mimic to m cancer or superficially protruded type with less component of protrusion. Regarding intraepithelial spread (ie), a complexed type with small ie lesion showed higher incidence of n (-) sm cancer than a simple type which has no ie lesion or a complexed type with large ie lesion (superficial spreading type). Histologically, differentiated type of squamous cell carcinoma, especially well-diff-erentiated type showed higher incidence of early cancer.

　2) Regarding complaints and sick period, n (+) sm cancer tend to have more complaints and larger sick days, however no significant differences from n (-) sm (+) cancer were noted. However, metastatic lymph nodes of n (+) sm cancer showed skipped metastasis to more than second district of lymph nodes, and its cumulative 5-year survival rate were 29% and much worse than n (-) sm cancer (85%). Therefore, it is important to evaluate a malignant degree of the cancer and to estimate the degree of invasion preoperatively by utilizing x-ray examination, endoscopy, CT scan, ultrasonography and endoscopic ultrasonography.

　3) Regarding radiological diagnosis of superficial cancer, superficial flat type and polypoid type had higher possibility of early cancer, but in other types, it was difficult to estimate whether they have metastasis or not by their type classification only. However, considering the following factors such as irregularity of the lesion, accompanied lesions and their characteristics, it is possible to estimate 〔ly, v〕 and 〔n〕 in superficial cancer.

　4) Endoscopic analysis showed depth of the superficial cancer had close relationship to endoscopic classification; sm cancer was mainly superficial protruded type or ulcer type and a part of erosion type was also included. Mixed type which consist of protruded type and erosive type and is not listed in a convention, showed very high incidence of vessel invasion and has poor prognosis.