進行胃癌の進行度診断体系update

Staging System Update for Advanced Gastric Cancer

要旨●胃癌の進行度診断は，壁深達度（T），リンパ節転移（N），その他の転移（M）を基準とする．「胃癌取扱い規約 第15版」では，胃癌の進行度は臨床分類と病理学的分類に分けられ，原発巣の進行度はT2とT3およびT4aとT4b，リンパ節転移はN0とN1〜3を鑑別する．いずれの診断も造影CTによる画像診断が基本となる．特に胃を拡張した状態で撮像する3次元CT（CT gastrography）は診断精度が高く有用である．また増強パターンにより病理組織学的診断を類推することができる．MRIは，肝転移の補助的診断として有用である．FDG-PETは，胃癌の進行度診断における貢献度は低い．

　The staging of gastric cancer is based on the depth of wall invasion（T）, lymph node metastasis（N）, and other metastases（M）. The 15th edition of the Japanese Classification of Gastric Carcinoma categorized the staging of gastric cancer into clinical and pathological classifications. The primary lesion should be differentiated as T2 vs. T3 and T4a vs. T4b, whereas lymph node metastasis is classified as N0 and N1 to N3. All diagnoses primarily rely on imaging with contrast-enhanced computed tomography（CT）. Three-dimensional CT gastrography, which captures images of the stomach in an expanded state, is highly accurate and useful. Additionally, enhancement patterns can be utilized to infer histopathological diagnoses. Magnetic resonance imaging is useful as an auxiliary diagnosis for liver metastasis. Fluorodeoxyglucose-positron emission tomography contributes little to the diagnosis of local and systemic spread of gastric cancer.