胃癌の深達度診断—拡大観察の位置づけ

Diagnosis of the Depth of Early Gastric Cancer by Magnifying Endoscopy

要旨●NBI併用拡大内視鏡（ME-NBI）による胃癌の深達度診断の報告は少ないが，SM浸潤を示唆する所見として太径血管の有無や毛細血管の断裂，粘膜表面の無構造化などが報告されている．今回はこれらの所見が深達度診断に有用であるかを検討した．2022年1月〜2024年5月に内視鏡的粘膜下層剝離術（ESD）で切除されたM癌174例と，2014年1月〜2024年5月までにESDで切除されたSM癌81例を対象とした．ME-NBIを用い，太径血管（RAC様血管，シアン調血管）の有無，表面微細構造の消失の有無，微小血管構築像の断裂の有無がSM浸潤を示唆する所見となり得るかをそれぞれの感度，特異度，陽性的中率，陰性的中率，陽性尤度比，陰性尤度比を求め検討した．SM浸潤を示唆する所見としてシアン調血管，MV patternの断裂がSM浸潤を示唆する所見として最も有用であった．一方で無構造化はSM浸潤と関連は乏しいと考えられた．

　Few reports have investigated the accuracy of NBI magnifying endoscopy for assessing invasion depth in gastric cancer. However, certain findings, such as the presence of large-caliber vessels, capillary disruption, and loss of mucosal surface structure, have been reported as potential indicators of submucosal（SM）invasion. In this study, we evaluated the diagnostic utility of these findings.

　We analyzed 174 cases of mucosal cancer resected by ESD between January 2022 and May 2024, and 81 cases of SM cancer resected by ESD between January 2014 and May 2024. Using magnifying endoscopy with NBI（ME-NBI）, we assessed whether the presence of large-caliber vessels（RAC-like vessels, cyan-color vessels）, the loss of surface microstructure, and the disruption of microvascular architecture could serve as indicators suggestive of SM invasion. For each finding, we calculated sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratios. Among the suspected indicators of SM invasion, cyan-pattern vessels, and microvascular patterns（MVP）disruptions were found to be the most reliable. However, structural loss showed little correlation with SM invasion.