Helicobacter pylori除菌後の胃癌

Gastric Cancer Discovered after Eradication Therapy

要旨　除菌治療は早期胃癌の内視鏡的発見率を減少させるが，その前提として正確な内視鏡診断が必要である．一方，既知の表面隆起型胃腫瘍症例に除菌治療を行うと，短期間で腫瘍形態が平坦化し，診断に苦慮する例がある．組織学的には腫瘍表面に低異型度上皮が出現する．除菌治療後にも胃癌は発見され，少数ながら進行癌として発見される症例もある．正常細胞が癌化し，内視鏡的に診断可能になるためには相当期間が必要であり，除菌治療により胃癌を抑制するためには，細胞レベルでの癌化が生じる前に介入を行う必要がある．

　Recent studies form Japan as well as overseas have demonstrated that eradication therapy reduced the rate of discovering early-stage gastric cancer. However, the effect was limited to the prevention of gastric cancer in the early stage, and a precise endoscopic diagnosis is essential. The eradication therapy influences the endoscopic and histologic morphology of cancer tissue, which may influence the cancer detection rate by endoscopy. It should be emphasized that some cancer lesions were detected in the advanced stage in spite of the cancer survey after eradication therapy. To achieve cancer prevention, the eradication should be carried out as early as possible, before single cancer cells develop in the gastric mucosa.