title: Short- and long-term outcomes of endoscopic resection of rectal neuroendocrine tumours: analyses according to the WHO 2010 classification.
abstract: OBJECTIVE
  Although the World Health Organisation (WHO) defined a novel classification of gastroenteropancreatic neuroendocrine tumours (NETs) in 2010, indications for endoscopic resection of rectal NETs in the guidelines were based on evidence accumulated for carcinoid tumours defined by a previous classification. This study was designed to clarify indications for endoscopic resection of rectal NETs corresponding to the new WHO classifications.
  
  
  METHODS
  One hundred-seventy rectal NETs resected endoscopically from April 2001 to March 2012 were histologically re-classified according to the WHO 2010 criteria. The clinicopathological features of these lesions were analysed, and the short- and long-term outcomes of endoscopic resection were evaluated.
  
  
  RESULTS
  Of the 170 rectal NETs, 166 were histopathologically diagnosed as NET G1 and four as NET G2. Thirty-eight tumours (22.4%) were positive for lymphovascular invasion, a percentage higher than expected. Although the curative resection rate was low (65.3%), en bloc (98.8%) and complete (85.9%) resection rates were high. Modified endoscopic mucosal resection (88.0%) and endoscopic submucosal dissection (92.2%) resulted in significantly higher complete resection rates than conventional endoscopic mucosal resection (36.4%). No patient experienced tumour recurrence, despite the low curative resection rate.
  
  
  CONCLUSIONS
  Despite the low curative resection rate, prognosis after endoscopic resection of rectal NETs was excellent. Prospective large-scale, long-term studies are required to determine whether NET G2 and tumours >1 cm should be included in the indication for endoscopic resection and whether tumours with lymphovascular invasion can be followed up without additional surgery.
authors.affiliation: a Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: b Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Mikako
authors.initials: M
authors.lastname: Osada
authors.affiliation: a Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Ayako
authors.initials: A
authors.lastname: Goto
authors.affiliation: a Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Iwasa
authors.affiliation: b Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: b Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Takizawa
authors.affiliation: c Department of Gastroenterology , Aso Iizuka Hospital , Iizuka , Japan ;
authors.forename: Kazuya
authors.initials: K
authors.lastname: Akahoshi
authors.affiliation: d Department of Internal Medicine , Saiseikai Fukuoka General Hospital , Fukuoka , Japan ;
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Ochiai
authors.affiliation: e Department of Gastroenterology , Harasanshin Hospital , Hakata-Ku , Fukuoka , Japan ;
authors.forename: Norimoto
authors.initials: N
authors.lastname: Nakamura
authors.affiliation: f Department of Gastroenterology , Kitakyushu Municipal Medical Center , Kokurakita-Ku , Kitakyushu , Japan ;
authors.forename: Hirotada
authors.initials: H
authors.lastname: Akiho
authors.affiliation: g Department of Gastroenterology , Kyushu Rosai Hospital , Kitakyushu, Fukuoka , Japan ;
authors.forename: Soichi
authors.initials: S
authors.lastname: Itaba
authors.affiliation: h Department of Gastroenterology , National Hospital Organization Kyushu Medical Center , Chuo-Ku , Fukuoka , Japan ;
authors.forename: Naohiko
authors.initials: N
authors.lastname: Harada
authors.affiliation: i Department of Gastroenterology , Fukuoka City Hospital , Hakata-Ku , Fukuoka , Japan ;
authors.forename: Moritomo
authors.initials: M
authors.lastname: Iju
authors.affiliation: j Department of Gastroenterology and Hepatology , National Hospital Organization Fukuoka Higashi Medical Center , Koga , Japan ;
authors.forename: Munehiro
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: k Department of Internal Medicine , Social Insurance Nakabaru Hospital , Shime-Machi , Kasuya-Gun , Japan ;
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kubo
authors.affiliation: l Department of Gastroenterology , National Hospital Organization Beppu Medical Center , Beppu , Oita Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Somada
authors.affiliation: a Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Eikichi
authors.initials: E
authors.lastname: Ihara
authors.affiliation: b Department of Anatomic Pathology, Pathological Sciences, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.affiliation: a Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Tetsuhide
authors.initials: T
authors.lastname: Ito
authors.affiliation: a Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences , Kyushu University , Higashi-Ku , Fukuoka , Japan ;
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Takayanagi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000145:classification / Q000601:surgery*; D011351:Proctoscopy; D012004:Rectal Neoplasms / Q000145:classification / Q000601:surgery*; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014944:World Health Organization; D055815:Young Adult
keywords: Endoscopic resection; indication; outcome; rectal neuroendocrine tumour