多発大腸癌の検討

A Study of Multiple Colorectal Cancers

要旨　多発大腸癌を同時性，異時性に分類して臨床的側面から検討を行った．対象は過去14年間で当科にて経験した多発大腸癌468病変，同時性多発癌134症例295病変，異時性多発癌64症例173病変であった．同時性，異時性ともに全体として肉眼形態，腫瘍径，占拠部位においては明確な差を認めなかったが，異時性において第2病変以降にLST，陥凹型病変の比率が上昇した．病理組織像において異時性癌ではm癌の比率が同時性よりも高かった．また異時性の進行癌例は4症例5病変が存在した．第1病変の発見から進行癌の出現までの期間は平均39.4か月であった．その背景因子を考察するとLSTや陥凹型病変の介在が示唆され，進行癌の発育進展を考察する上でも興味深いと考えられた．

　It is generally known that cases of multiple colorectal carcinomas have been increasing recently. The reason for this is that the number of examinations by colorectal endoscopy has increased and especially patients who have undergone colonoscopic examinations several times have been increasing. The present study was carried out to clarify the characteristics of multiple colorectal carcinomas from the viewpoint of clinical features. During the period from April, 1985 to April, 1999 we had encountered 197 cases which included 468 lesions of multiple colorectal cancers. We divided them into two groups as follows, the synchronous group in which we discovered several cancers within one year (134 cases 295 lesions), and metachronous group in which we discovered several cancers in a period of over one year (64 cases 173 lesions). As a result, we recognized that the ratio of LST (laterally spreading tumors) and depressed type cancers was increasing among the second and third lesions of the metachronous group. The rate of mucosal cancer in the metachronous group was higher than that in the synchronous group. There were five advanced cancers without first lesions in the metachronous group, during a mean period of 39.4 months. It is considered that LST and depressed type lesions have relation to a background of metachronous cancers, and we are greatly interested in this fact for its bearing on the development and growth of cancer.