title: Tumor size correlates with malignancy in nonfunctioning pancreatic endocrine tumor.
abstract: BACKGROUND
  Tumor size is a criterion of staging in nonfunctioning pancreatic endocrine tumors as well as a predictor of outcome after curative resection. This study analyzes the correlation between tumor size and malignancy in patients with nonfunctioning pancreatic endocrine tumors.
  
  
  METHODS
  All patients with nonfunctioning pancreatic endocrine tumors who underwent curative resection (R0) at our institution between 1990 and 2008 were considered. Their clinicopathologic characteristics were compared among 3 different groups according to tumor size. Univariate and multivariable analyses were performed.
  
  
  RESULTS
  Over the study period, 177 patients were identified. Overall, 90 patients (51%) had a tumor size ≤2 cm (group 1), 46 (26%) had tumor size between >2 cm and ≤4 cm (group 2), and 41 (23%) had tumor size >4 cm (group 3). Tumors ≤2 cm were more frequently incidentally discovered (group 1, 57% vs group 2, 51% vs group 3, 32%; P = .014) and benign (group 1, 81% vs group 2, 65% vs group 3, 5%; P < .0001). The presence of a nonfunctioning pancreatic endocrine tumor >2 cm and a nonincidental diagnosis of the tumor were independent predictors of malignancy at multivariable analysis. None of the 51 patients (29%) with a pancreatic endocrine tumor ≤2 cm that was incidentally diagnosed died of disease.
  
  
  CONCLUSIONS
  A strict correlation between tumor size and malignancy in nonfunctioning pancreatic endocrine tumors was demonstrated. A nonoperative management could be advocated for tumors ≤2 cm when discovered incidentally.
authors.affiliation: Department of Surgery, S. Cuore-Don Calabria Hospital, Negrar, Verona, Italy.
authors.forename: Rossella
authors.initials: R
authors.lastname: Bettini
authors.forename: Stefano
authors.initials: S
authors.lastname: Partelli
authors.forename: Letizia
authors.initials: L
authors.lastname: Boninsegna
authors.forename: Paola
authors.initials: P
authors.lastname: Capelli
authors.forename: Stefano
authors.initials: S
authors.lastname: Crippa
authors.forename: Paolo
authors.initials: P
authors.lastname: Pederzoli
authors.forename: Aldo
authors.initials: A
authors.lastname: Scarpa
authors.forename: Massimo
authors.initials: M
authors.lastname: Falconi
mesh_terms: D007516:Adenoma, Islet Cell / Q000473:pathology* / Q000601:surgery; D000328:Adult; D000368:Aged; D018273:Carcinoma, Islet Cell / Q000473:pathology* / Q000601:surgery; D002454:Cell Differentiation; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D012307:Risk Factors