疫学および病理学の立場からみた食道癌と他臓器重複癌

Multiple Primary Cancer in Patients with Esophageal Cancer

　食道扁平上皮癌患者の他部位との重複癌を種々の面より検討した．発生率を部位別，期間別に一般人とのO/E比を検討した結果，頭頸部(特に口腔・咽頭)が最も有意に発生率が高く，術後10年以上でも有意に高かった．数が多かった胃癌は，O/E比でみると1年未満のみに有意な差がみられ，術後の精密検査のための発生率の高さと思われた．食道多発癌は頭頸部との重複癌が有意に多かった(p＝0.001)．まだら食道は非まだら食道に比べて有意に多発癌が多く(p＝0.0440)，頭頸部との重複癌も多い傾向にあった(p＝0.0598)．喫煙・飲酒は重複癌の要因として重要であった．以上の結果より，食道癌患者は特に頭頸部を中心に10年以上にわたって経過観察が必要であると結論した．またこれらを予防するには，禁煙が重要であると思われた．

　Multiple primary cancer in patients with esophageal cancer is studied from the aspect of epidemiology and pathology.

　The most significant high-risk region for second primary cancer was the head and neck region, especially the mouth and pharynx with an odds ratio 16.5 (95 ％ CI 6.0-36.0). Even when the period between the primary and secondary cancer is over 10 years, the odds ratio was 37.5 (95 ％ CI 4.2-135.4).

　In a stomach cancer, which has the highest incidence of second primary cancer, however, the odds ratio was not significant as compared with that of the general population.

　Patients with multi-centric squamous cell carcinoma of the esophagus were at significantly high-risk to develop second primary head and neck cancer as compared with single esophageal cancer (p＝0.001).

　Patients with squamous cell carcinoma with multi-unstained areas by Lugol-stain were at significantly high-risk to develop multi-centric squamous cell carcinomas in the esophagus (p＝0.044) and were at higher risk to develop multiple-primary cancer (p＝0.0598).

　Smoking and drinking habits were the most important factors involved in multiple primary cancer in patients with esophageal cancer.

　Clinically, patients with esophageal cancer, especially multi-centric cancers, should be carefully followed up for 10 years after diagnosis of esophageal carcinoma.

　To prevent multiple primary cancer, refraining from smoking and drinking was the most important measure to be taken.