経過観察例からみた胃癌ハイリスクグループ―胃X線検査の立場から

Patients at High Risk of Gastric Cancer according to Follow-up Study of Upper GI Series

要旨　癌検診を契機に発見された胃癌51例について，X線像から遡及的に胃の萎縮状態を評価し，胃癌のハイリスクグループを選別できるかを検討した．遡及的（平均期間50.6か月）に評価した胃のX線的萎縮度は，萎縮軽度な群が29例（57％）と最も多く，この群から22例の分化型癌が認められた．この結果から“萎縮の少ない胃であっても，相当数の分化型癌が発生する”ことが判明した．胃全域の萎縮が軽度と判定されても，局所的には腸上皮化生粘膜が存在する．こういった粘膜は分化型癌の組織発生母地となることから，萎縮の軽度な胃でも胃癌のリスクが低いとは断言できないと考えられた．

　We examined whether it is possible to identify patients at high risk of gastric cancer according to mucosal atrophy demonstrated by upper GI series in a retrospective study in 51 cases of gastric cancer detected on cancer screening. The retrospective evaluation（average observation time : 50.6 months）of the degree of atrophy by upper GI series showed that mild atrophy was most common, and 29 cases（57％）included 22 lesions of well-differentiated carcinoma. These observations indicated that substantial well-differentiated carcinoma developed even on less atrophic mucosa.

　Although the mucosa in the whole stomach was diagnose as showing mild atrophic gastritis, there may be focal intestinal metaplasia that could develop into histologically well-differentiated carcinoma. Therefore, findings of mild atrophic changes of the stomach mucosa cannot exclude the risk of gastric cancer.