SNADETの疫学―微小病変の臨床的取り扱いに関する考察を含めて―

Epidemiology of SNADETs―treatment for diminutive SNADETs based on the epidemiology―

要旨

近年，欧米で十二指腸癌は増加傾向であり，最近，本邦における非乳頭部十二指腸癌の罹患率が欧米に比し高いことが判明した。実際に本邦において日常臨床で表在性非乳頭部十二指腸上皮性腫瘍（SNADET）に遭遇する機会は急速に増加している。他の消化管に比し，内視鏡切除の合併症頻度と重篤性が高かったため，腺腫であれば経過観察も容認されてきた。しかし，最近の内視鏡切除手技の進歩によって，その安全性が確保されつつあり，腺腫の臨床的取り扱いに関する考えが大きく変化している。本稿ではSNADETの疫学と自然史に関する文献的考察を加えるとともに，微小な腺腫を含めた最適な取り扱い指針について考察したい。

　In recent years, the incidence of duodenal cancer has been increasing in Europe and the United States. A resent epidemiological survey showed that the prevalence of non-papillary duodenal cancer in Japan is higher than in the United States. In fact, the chances of encountering superficial non-ampullary duodenal epithelial tumor (SNADET) in practical endoscopy in Japan are rapidly increasing. A wait-and-see strategy has been accepted for adenomas, especially for low-grade ones in the non-ampullary sites of the duodenum because of the high frequency and severity of complications associated with endoscopic resection compared to other gastrointestinal tracts. However, recent advances in endoscopic resection techniques have ensured their safety and have significantly changed the way we think about the clinical management of adenomas. In this article, we conduct a review of the epidemiology and natural history of SNADET in the literature, and discuss the optimal strategy for handling adenomas including diminutive lesions less than 5mm in diameter.