多発早期胃癌の臨床病理学的検討―外科的立場から

Clinico-pathological Study on Synchronous Multiple Early Gastric Cancer: From the Standpoint of Surgery

要旨　当外科開設以来17年6か月間に切除された早期胃癌428例のうち，同時性多発癌は57例（13.3％），147病変であった．年齢および性別では単発早期胃癌の平均年齢が57.4歳であったのに対し，多発癌では62.8歳で，男女比は5.3：1と高齢者男性に圧倒的に多くみられた．肉眼型はⅡcを主体とした陥凹型が73病変（49.7％）を占め，Ⅱb型34病変（23.1％），隆起型が40病変（27.2％）となり，陥凹・平坦型で72.8％を占めている．その組み合わせは陥凹性病変では陥凹型同士の組み合わせが51.4％にみられたが，隆起性病変では隆起型との併存は35.0％で残りは陥凹型と平坦型の組み合わせであった．これは，胃全割標本による組織学的検索により術前指摘しえなかった微小多発癌巣が多いことに起因している．一方，主病巣と副病巣の位置関係をみると噴門側に副病巣が存在する頻度は43.8％もあり，術前の噴門側粘膜の十分な精査が必要となる．また，腺領域別には胃底腺領域に発生した未分化型腺癌はわずか2病変にしかすぎず，分化型，未分化型癌とも，そのほとんどは萎縮領域を幽門腺領域に発生していた．これら多発早期胃癌の背景粘膜をみると，まず単発の分化型腺癌症例ではびまん広範腸上皮化生粘膜が48.9％であったのに対し，多発癌では80％までが高度かつ密な腸上皮化生粘膜を背景病変としていた．更に多発胃癌は腺腫を併存している頻度が高く，14.3％に腺腫を合併していた．以上の事実から，高齢者，男性で高度の腸上皮化生を伴った萎縮粘膜のみられる胃では，多発胃癌の可能性を念頭に置いての臨床対応が必要と言える．

　Multiple cancers of the stomach are not uncommon, and surgeons are sometimes confused with the appropriate proximal incision site of gastrectomy. The clinico-pathological study may contribute surgical decision making for multiple gastric cancers. Over the last 17 years (1975-1992), 428 cases with early gastric cancer were resected in our department. Multiple cancers were detected in 57 cases which accounted for 13.3% of the resected cases. The age of patients was widely distributed from 26 to 85 years and the average was 62.8 years. The incidence of multiple cancers progressed with age. Many lesions were located in the atrophic area; there were only 2 lesions lesions located in the fundie gland area. Multiple minute cancers of the flat but depressed type were unexpectedly found as incidental findings. Histologically differentiated type cancer (tubular and papillary adenocarcinoma) was common (116 lesions, 78.9%) and undifferentiated type cancers (poorly differentiated and signet-ring cell carcinoma) accounted for only 31 lesions (21.2%). Most of the differentiated type cancer were accompanied by extensively atrophic gastritis with severe intestinal metaplasia for the background. There proved to be a close relationship between differentiated type multiple gastric cancers and intestinal metaplasia. Out of those 57 cases with multiple gastric cancers, the multiplicity was preoperatively diagnosed only in 37 cases. Most lesions were detected as minute cancers by serial sectioning of the resected stomach. Therefore it is very important to find the border between the fundic gland and the atrophic area preoperatively. At the time of gastrectomy, wide resection and careful examination of the remnant stomach is recommended.