title: Operative Versus Nonoperative Management of Nonfunctioning Pancreatic Neuroendocrine Tumors.
abstract: BACKGROUND
  Surgical resection is the only curative treatment for pancreatic neuroendocrine tumors (PNETs), but pancreatic operations carry a significant morbidity. We investigated whether the resection of small, asymptomatic nonfunctioning PNETs is beneficial. Clinicopathologic factors were retrospectively reviewed for all PNET cases from 1998 to 2014.
  
  
  METHODS
  Kaplan-Meier survival and multivariable regression analyses were performed. A total of 249 patients had nonfunctioning PNETs with adequate follow-up, of whom 193 were resected and 56 were observed. Median age was 56 years, and 48 % of the patients were female.
  
  
  RESULTS
  Overall, the resected patients had a significantly longer survival (OS) (p = 0.001). However, for the patients with PNETs ≤2.5 cm in size and without metastasis at presentation, tumor size significantly modified the effect of resection on overall survival (p < 0.05). The protective effect of resection increased as tumor size increased. An operation became a significant predictor of overall survival for tumors >1.5 cm (p = 0.050 or less for larger tumors) but was not significant for tumors <1.5 cm (p = 0.317 or more for smaller tumors), controlling for age-adjusted Charlson comorbidity index.
  
  
  CONCLUSIONS
  Resection of nonfunctioning PNETs over 1.5 cm is independently and significantly associated with a longer survival. However, the benefit of resection for tumors under 1.5 cm is unclear.
authors.affiliation: Massachusetts General Hospital, Wang 460, 15 Parkman Street, Boston, MA, USA.
authors.forename: Irene Y
authors.initials: IY
authors.lastname: Zhang
authors.affiliation: Massachusetts General Hospital, Wang 460, 15 Parkman Street, Boston, MA, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Massachusetts General Hospital, Wang 460, 15 Parkman Street, Boston, MA, USA.
authors.forename: Carlos
authors.initials: C
authors.lastname: Fernandez-Del Castillo
authors.affiliation: Massachusetts General Hospital, Wang 460, 15 Parkman Street, Boston, MA, USA.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Braun
authors.affiliation: Massachusetts General Hospital, Wang 460, 15 Parkman Street, Boston, MA, USA.
authors.forename: Shadi
authors.initials: S
authors.lastname: Razmdjou
authors.affiliation: Massachusetts General Hospital, Wang 460, 15 Parkman Street, Boston, MA, USA.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Warshaw
authors.affiliation: Massachusetts General Hospital, Wang 460, 15 Parkman Street, Boston, MA, USA.
authors.forename: Keith D
authors.initials: KD
authors.lastname: Lillemoe
authors.affiliation: Massachusetts General Hospital, Wang 460, 15 Parkman Street, Boston, MA, USA. cferrone@partners.org.
authors.forename: Cristina R
authors.initials: CR
authors.lastname: Ferrone
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D010190:Pancreatic Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery*; D018579:Patient Selection; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult
keywords: Nonfunctioning; Pancreatic neuroendocrine tumor; Resection; Size; Surgery