title: Ki-67 Index and Solid Growth Pattern as Prognostic Markers in Small Intestinal Neuroendocrine Tumors.
abstract: OBJECTIVE
  The prognostic value of histopathological grading and the growth pattern of small intestinal neuroendocrine tumors (SI-NET) is unclear. In particular, the cutoff level between grades G1 and G2 at Ki-67 index above 2% is an open issue, and both lower and higher cutoffs have been proposed. The morphological solid growth pattern (SGP) in SI-NET has been reported to be associated with worse survival. The present study investigates whether a Ki-67 index cutoff of 1% has a higher predictive power than one of 2% for disease-specific survival in SI-NET, and whether an SGP is associated with survival.
  
  
  METHODS
  From a population-based cohort, 127 SI-NET patients with available tumor specimens were included. Medical records and pathology reports were reviewed. Tumor specimens were reexamined to confirm the diagnosis, recalculate the Ki-67 index, and assess the presence of an SGP, introducing an SGP score from 0 to 3+.
  
  
  RESULTS
  The current grading system with a G1/G2 cutoff of 2% was more discriminative (HR 2.30; 95% CI 1.20-4.38, p = 0.012) than one with a lower cutoff of 1% (HR 1.65; 95% CI 0.95-2.87, p = 0.078) after adjustment for patient age and clinical stage. SGP score was strongly associated with clinical stage (p = 0.004) and histopathological grade (p < 0.001) but was not an independent prognostic factor for disease-specific survival in SI-NET (p = 0.122) after adjusting for age, stage, and grade.
  
  
  CONCLUSIONS
  The present grading system of SI-NET is supported by our results. The SGP is not an independent prognostic factor for disease-specific survival in SI-NET.
authors.affiliation: Department of Surgery, Ryhov County Hospital, Jx00F6;nkx00F6;ping, Sweden.
authors.forename: Kalle
authors.initials: K
authors.lastname: Landerholm
authors.forename: Sture E
authors.initials: SE
authors.lastname: Falkmer