Epidemiological study of gastroenteropancreatic neuroendocrine tumors in Japan

• DOI: 10.1007/s00535-009-0194-8
• Publication Date: 2010-01-08T03:07:03Z
• Authors: Tetsuhide Ito; Hironobu Sasano; Masao Tanaka; R. Yoshiyuki Osamura; Iwao Sasaki; Wataru Kimura; Koji Takano; Takao Obara; Miyuki Ishibashi; Kazuwa Nakao; Ryuichiro Doi; Akira Shimatsu; Toshirou Nishida; Izumi Komoto; Yukio Hirata; Kazuhiko Nakamura; Hisato Igarashi; Robert T. Jensen; Bertram Wiedenmann; Masayuki Imamura
• Keywords: Adult; Aged, 80 and over; Male; Adolescent; Data Collection; Incidence; Middle Aged; 3. Good health; Pancreatic Neoplasms; Neuroendocrine Tumors; Young Adult; 03 medical and health sciences; Age Distribution; 0302 clinical medicine; Japan; Prevalence; Humans; Female; Neoplasm Metastasis; Child; Aged; Gastrointestinal Neoplasms

There have been few epidemiological studies on gastroenteropancreatic neuroendocrine tumors (GEP-NETs) in Japan.We examined the epidemiology of GEP-NETs [pancreatic endocrine tumors (PETs) and gastrointestinal neuroendocrine tumors (GI-NETs)] in Japan in 2005 using a nationwide stratified random sampling method.A total of 2,845 individuals received treatment for PETs. Prevalence was estimated as 2.23/100,000 with an annual onset incidence of 1.01/100,000. Non-functioning tumor (NF)-PET constituted 47.4%, followed by insulinoma (38.2%) and gastrinoma (7.9%). Distant metastases were reported in 21% patients with NF-PETs and occurred more frequently as tumor size increased (>2 cm). Multiple endocrine neoplasia type 1 (MEN-1) was detected in 10% of PETs but only in 6.1% of NF-PETs. NF-PETs were detected incidentally by physical examination in 24% patients. In 2005, an estimated 4,406 patients received treatment for GI-NETs. Prevalence was estimated as 3.45/100,000, with an annual onset incidence of 2.10/100,000. The locations of GI-NETs varied: foregut, 30.4%; midgut, 9.6%; and hindgut, 60.0%. Distant metastases were observed in 6%. Lymph node metastases occurred more frequently as tumor size increased (>1 cm). The frequency of MEN-1 complications was 1%. Physical examination revealed GI-NETs in 44% patients. The frequency of symptomatic GI-NETs was 3.4%. Interestingly, 77.1% of patients with foregut GI-NETs had type A gastritis.Our results show there are large differences in GEP-NETs between Japan and Western nations, primarily due to differences in the presence of MEN-1 in NF-PETs and the location, symptomatic status, and prevalence of malignancy in GI-NETs.