title: Prognostic significance of lymph node metastases in small intestinal neuroendocrine tumors.
abstract: OBJECTIVE
  Current staging guidelines for small intestinal neuroendocrine tumors (SI-NETs) differentiate between the presence (N1) and absence (N0) of lymph node (LN) metastases. However, the prognostic significance of the extent of LN involvement remains unknown. In this study, we used data from a population-based cancer registry to examine whether involvement of a higher number of LNs is associated with worse survival.
  
  
  METHODS
  We used the Surveillance, Epidemiology, and End Results (SEER) database to identify patients with histologically confirmed, surgically resected SI-NETS diagnosed between 1988 and 2010. Patients were classified into three groups by the LN ratio (number of positive LNs/number of total LNs examined, LNR): ≤0.2, >0.2-0.5, and >0.5. We used the Kaplan-Meier method and Cox models to assess NET cancer-specific survival differences (up to 10 years from diagnosis) according to LNR status.
  
  
  RESULTS
  We identified 2,984 surgically resected patients with stage IIIb (N1, M0) SI-NETs with detailed LN data. More than half of the NETs were located in the ileum. A higher LNR was significantly associated with worse NET cancer-specific survival (p < 0.0001). Ten-year NET-specific survival was 85, 77, and 74% for patients in the ≤0.2, >0.2-0.5, and >0.5 LNR groups, respectively. In stratified analyses, higher LNR groups had worse survival only in early tumor (T1, T2) disease (p < 0.0001).
  
  
  CONCLUSIONS
  The extent of LN involvement provides independent prognostic information on patients with LN-positive SI-NETs. This information may be used to identify patients at high risk of recurrence and inform decisions about the use of adjuvant therapy.
authors.affiliation: Division of Gastroenterology, Department of Medicine, Mount Sinai School of Medicine, New York, N.Y., USA.
authors.forename: Michelle Kang
authors.initials: MK
authors.lastname: Kim
authors.forename: Richard R P
authors.initials: RR
authors.lastname: Warner
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Ward
authors.forename: Noam
authors.initials: N
authors.lastname: Harpaz
authors.forename: Sasan
authors.initials: S
authors.lastname: Roayaie
authors.forename: Myron E
authors.initials: ME
authors.lastname: Schwartz
authors.forename: Steven
authors.initials: S
authors.lastname: Itzkowitz
authors.forename: Juan
authors.initials: J
authors.lastname: Wisnivesky
mesh_terms: D005260:Female; D006801:Humans; D007414:Intestinal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000401:mortality; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000175:diagnosis* / Q000453:epidemiology* / Q000401:mortality; D011379:Prognosis