title: Neuroendocrine tumors of the colon and rectum: prognostic relevance and comparative performance of current staging systems.
abstract: BACKGROUND
  With increasing interest in neuroendocrine tumors (NETs), three staging systems for NETs of the colon and rectum have been published. Their prognostic relevance has not been examined and compared in an independent clinical database.
  
  
  METHODS
  From the National Cancer Database (NCDB), 5457 patients diagnosed with colorectal neuroendocrine tumor (CRNETs) between 1998 and 2002 were staged according to the staging systems from (1) European Neuroendocrine Tumor Society (ENETS, 2006; n = 1537); (2) American Joint Committee on Cancer (AJCC, 2009; n = 1140); and (3) location-specific staging systems from the Surveillance Epidemiology and End Results (SEER, 2008; n = 942). Stage-stratified overall survival (OS) and Cox-specific concordance indices were calculated for each system. Independent prognostic factors were identified by multivariate analysis.
  
  
  RESULTS
  Five-year OS for stage I, II, III, and IV CRNETs as defined by the ENETS staging system were 90.8, 77.3, 53.1, and 14.8 %, respectively. For well-differentiated CRNETs, the 5-year OS for stage I, II, III, and IV as defined by the AJCC staging system were superior: 90.6, 83.9, 64.8, and 24.9 %, respectively. Both staging systems had a concordance index of 0.72. After specifying location in the colon versus rectum, all three systems demonstrated acceptable performance. Histologic grade was a significant independent predictor of OS not currently incorporated in the staging systems.
  
  
  CONCLUSIONS
  The three staging systems showed comparable prognostic stratification of CRNETs, while the AJCC and ENETS systems are the most parsimonious. The current analysis supports the use of the AJCC for well-differentiated disease and ENETS systems for all CRNETs until there is further evidence for modification.
authors.affiliation: Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Ryaz
authors.initials: R
authors.lastname: Chagpar
authors.forename: Yi-Ju
authors.initials: YJ
authors.lastname: Chiang
authors.forename: Yan
authors.initials: Y
authors.lastname: Xing
authors.forename: Janice N
authors.initials: JN
authors.lastname: Cormier
authors.forename: Barry W
authors.initials: BW
authors.lastname: Feig
authors.forename: Asif
authors.initials: A
authors.lastname: Rashid
authors.forename: George J
authors.initials: GJ
authors.lastname: Chang
authors.forename: Y Nancy
authors.initials: YN
authors.lastname: You
mesh_terms: D000368:Aged; D003110:Colonic Neoplasms / Q000145:classification / Q000401:mortality* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging / Q000592:standards*; D018358:Neuroendocrine Tumors / Q000145:classification / Q000401:mortality* / Q000556:secondary; D011379:Prognosis; D012004:Rectal Neoplasms / Q000145:classification / Q000401:mortality* / Q000473:pathology; D012042:Registries; D015996:Survival Rate