転移陽性が疑われる胃粘膜内癌の取り扱い―縮小手術を含めて

Treatment of Gastric Mucosal Cancer with Lymph Node Metastasis

要旨　近年，診断システム向上などによる早期胃癌の増加と手術技術の進歩に伴い，早期胃癌に対する様々な縮小手術が導入されてきた．リンパ節転移は早期胃癌の約10％に認められ縮小手術適応決定には最重要な因子である．また遠隔転移や腹膜播種を呈する悪性度の高い早期胃癌の予測も縮小手術適応決定に重要であろう．本稿では胃粘膜内癌（胃M癌）のリンパ節転移，遠隔転移および腹膜播種に関する検討を行い，その結果，転移危険因子として，①陥凹型病変，②大きい（腫瘍径4cm以上の腫瘍），③組織型が未分化型，④潰瘍瘢痕〔UL(＋)〕が抽出された．一方，当院で行われているsentinel node theoryに基づいたリンパ節転移診断に関する臨床研究を示した．術前にisotope labeling粒子を腫瘍近傍粘膜下層に局注し，sentinel lymph node（SN）の同定，迅速病理組織診断によるリンパ節転移診断を行っている．その高い正診率が確認され，現在，腹腔鏡下胃切除術にも補助診断法として導入している．リンパ節診断として有力な概念sentinel node navigation surgeryのもと，今後のさらなる早期胃癌治療の工夫（縮小化）が期待される．

　Recent development of a diagnostic system for gastric cancer in Japan has increased the population of patients with early gastric cancer, who are treated with various kinds of minimized surgery with improved surgical devises and skill. Diagnosis of lymph node, distant, or peritoneal metastasis is critical for determining the indication for minimized surgery against gastric cancer, because such metastases are observed in patients (around 10％) of early gastric cancer. In this report, we evaluate clinico-pathological factors that can be suggested as risk indicators for metastasis in gastric mucosal cancer (M cancer). They are : ( 1 ) depressed lesion, ( 2 ) large size (over 4cm in diameter), ( 3 ) histologically, undifferentiated type, ( 4 ) ulceration in lesion. On the other hand, clinical research for sentinel node navigation surgery in our hospital showed good results in intra-operative diagnosis for lymph node metastasis, showing a high accuracy rate elucidated by pathological diagnosis of sentinel lymph nodes, which were identified by investigation using isotope labeling tin-colloids injected into the submucosal layer near the cancer lesion. We have applied the sentinel node navigation in laparoscopic gastric surgery, and we consider that the concept of sentinel node navigation surgery might be a novel approach leading to minimized invasiveness in therapy against early gastric cancer.