title: Surgical treatment of neuroendocrine tumors in the second portion of the duodenum: a single center experience and systematic review of the literature.
abstract: OBJECTIVE
  The treatment of choice for duodenal neuroendocrine tumors (NETs) ranges from endoscopic resection and local excision to pancreaticoduodenectomy. The aim of this study was to investigate the optimal treatment for this tumor.
  
  
  METHODS
  We retrospectively analyzed the clinicopathological data of 14 patients with NETs in the second portion of the duodenum who underwent surgery in our hospital from 2000 to 2015. The duodenal NETs were classified as either ampullary or non-ampullary. Additionally, a systematic review and pooled analysis was conducted.
  
  
  RESULTS
  Among eight patients with ampullary NETs and six patients with non-ampullary NETs, seven and three patients underwent pancreaticoduodenectomy and one and three patients underwent local resection, respectively. The maximum tumor diameter were 11-30 mm in ampullary and 10-100 mm in non-ampullary NETs, respectively. In patients with ampullary NETs, lymph node metastases were suspected in only three cases preoperatively, but five patients actually had regional nodal metastases. Among patients with non-ampullary NETs, lymph node metastases were suspected in none preoperatively, but three of the four patients who underwent lymph node dissection had regional nodal metastases. According to a pooled analysis of 1245 patients in 88 studies, even small tumors confined to the submucosal layer and G1 tumors-ampullary and non-ampullary-have been associated with lymph node metastases. In patients with non-ampullary NETs and lymph node metastasis, 10-year recurrence-free survival rate was 51% for patients who underwent pancreaticoduodenectomy (n = 19) and 53% for patients who underwent partial duodenal resection (n = 9), respectively (p = 0.960).
  
  
  CONCLUSIONS
  Lymph node metastases were common in association with both ampullary and non-ampullary NETs, and it was difficult to radiologically diagnose metastases. Additionally, there were no clinicopathological factors that could reliably predict the absence of lymph node metastases preoperatively. Therefore, to maximize the ability to achieve a curative resection, pancreaticoduodenectomy is considered appropriate in well-conditioned patients with NETs in the second portion of the duodenum. However, to further clarify the impact of lymph node dissection on survival after duodenal NET resection, a multi-institutional study with a large number of patients, thorough examination of lymph node metastasis, and a long observation period is warranted.
authors.affiliation: Hepatobiliary and Pancreatic Surgery Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Iwasaki
authors.affiliation: Hepatobiliary and Pancreatic Surgery Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan. sanara@ncc.go.jp.
authors.forename: Satoshi
authors.identifier: http://orcid.org/0000-0002-3516-8765
authors.initials: S
authors.lastname: Nara
authors.affiliation: Hepatobiliary and Pancreatic Surgery Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kishi
authors.affiliation: Hepatobiliary and Pancreatic Surgery Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Esaki
authors.affiliation: Hepatobiliary and Pancreatic Surgery Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Shimada
authors.affiliation: Division of Pathology and Clinical Laboratories, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
authors.forename: Nobuyoshi
authors.initials: N
authors.lastname: Hiraoka
mesh_terms: D000046:Academic Medical Centers; D000368:Aged; D016009:Chi-Square Distribution; D015331:Cohort Studies; D018572:Disease-Free Survival; D004379:Duodenal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D008197:Lymph Node Excision / Q000379:methods*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D010180:Pancreatectomy / Q000009:adverse effects / Q000379:methods; D016577:Pancreaticoduodenectomy / Q000009:adverse effects / Q000379:methods*; D011183:Postoperative Complications / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D011379:Prognosis; D018570:Risk Assessment; D016019:Survival Analysis; D047368:Tumor Burden
keywords: Duodenum; Lymph node; Neuroendocrine tumor; Pancreaticoduodenectomy