右側発生早期大腸癌の臨床的特徴

Clinical Features of Right-sided Early Colorectal Cancer

要旨　右側大腸に多く癌を発生する疾患として，遺伝性非ポリポーシス大腸癌〔HNPCC（hereditary non-polyposis colorectal cancer），Lynch症候群〕，大腸鋸歯状病変（特にsessile serrated adenoma/polyp ; SSA/P），虫垂癌が挙げられる．HNPCCは若年発症，右側大腸癌，大腸多発癌，多臓器重複癌を特徴とする常染色体優性遺伝性疾患であり，約90％にマイクロサテライト不安定性（microsatellite instability ; MSI）を認める．SSA/Pは右側結腸MSI陽性大腸癌の前駆病変の1つであり，SSA/P併存癌は高齢者，女性，右半結腸に多く存在し，進行癌を除いた早期癌に限ると無茎型病変が多い．また，M癌とSM癌間では病変全体の大きさに有意差はないが，SSA/P部を除いた癌部の大きさではSM癌が有意に大きかったという報告がある．原発性虫垂癌は，比較的まれな疾患であるが，42例の報告によると，平均年齢は62.0歳で，男性18例，女性24例であったとされている．

　As a disease to often generate a colorectal cancer of the right side colon is〔HNPCC（the hereditary nonpolyposis colorectal cancer）, Lynch syndrome〕, serrated lesion of the colon〔include in particular SSA/P（sessile serrated adenoma/polyp）〕, appendix cancer. HNPCC is young onset, right-sided colon cancer, a large intestine-prone cancer, the autosomal dominant hereditary disease characterized by many organs overlap cancer, and accepts MSI（microsatellite instability）in approximately 90％. SSA/P is one of the outrider lesions of MSI-positive right-sided colon cancer, there is a lot SSA/P coexistence cancer to elderly person, woman and right-sided colon, and there are many sessile type lesions only for an early cancer except the advanced cancer. In addition, size of the whole lesion does not have the significant difference between the M cancer and the SM cancer, but there is the report that SM cancer was significantly large with the size of the cancer region except the SSA/P region. Primary appendix cancer is a relatively rare disease, but the average age is 62.0 years old, and, according to 42reports, it is said that it was 18men, woman 24.