title: Increasing incidence of duodenal neuroendocrine tumors: Incidental discovery of indolent disease?
abstract: BACKGROUND
  There has been a marked increase in the recognized incidence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Studies have often combined duodenal neuroendocrine tumors (D-NETs) with other small bowel GEP-NETs. As a result, the natural history and clinical ramifications of these D-NETs is poorly understood.
  
  
  METHODS
  Patients diagnosed with duodenal "carcinoid" tumors from 1983 to 2010 were identified in the Surveillance Epidemiology and End Results tumor registry.
  
  
  RESULTS
  A total of 1,258 patients were identified. The mean age was 64 years. The majority of patients were male (55.6%), white (55.6%), and had stage I disease (66.2%). Patients meeting inclusion criteria were divided into 2 cohorts: (i) era 1 patients diagnosed with GEP-NETs from 1983 to 2005, and (ii) era 2 those diagnosed from 2005 to 2010. There was a clear increase in the incidence rate of D-NETs from 0.27 per 100,000 in 1983 to 1.1 per 100,000 in 2010 (P < .001). Comparison of patients from the different eras revealed that those in era 2 were more likely than era 1 to present with stage I disease (69.9 vs 57.5%; P < .01) and less likely to present with late-stage disease. The 5-year, disease-specific survival improved for era 2 patients compared with era 1 (89.3 vs 85.2%; P = .05); however, multivariate analysis demonstrated that stage but not era was associated with disease-specific survival.
  
  
  CONCLUSIONS
  Prognosis for D-NETs, in contrast with other small bowel NETs, is excellent. There has been a steady increase in the recognized incidence of D-NETs, coincident with the migration to earlier disease stage and improved disease-specific survival.
authors.affiliation: Brody School of Medicine, Division of Surgical Oncology, East Carolina University, Greenville, NC. Electronic address: fitzgeraldt@ecu.edu.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Fitzgerald
authors.affiliation: Brody School of Medicine, Division of Surgical Oncology, East Carolina University, Greenville, NC.
authors.forename: Samuel O
authors.initials: SO
authors.lastname: Dennis
authors.affiliation: Brody School of Medicine, Division of Surgical Oncology, East Carolina University, Greenville, NC.
authors.forename: Swapnil D
authors.initials: SD
authors.lastname: Kachare
authors.affiliation: Brody School of Medicine, Division of Surgical Oncology, East Carolina University, Greenville, NC.
authors.forename: Nasreen A
authors.initials: NA
authors.lastname: Vohra
authors.affiliation: Brody School of Medicine, Division of Surgical Oncology, East Carolina University, Greenville, NC.
authors.forename: Emmanuel E
authors.initials: EE
authors.lastname: Zervos
mesh_terms: D000328:Adult; D000368:Aged; D002276:Carcinoid Tumor / Q000175:diagnosis / Q000453:epidemiology*; D004379:Duodenal Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D015994:Incidence; D033162:Incidental Findings; D007414:Intestinal Neoplasms / Q000175:diagnosis / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000453:epidemiology; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000453:epidemiology; D011379:Prognosis; D016016:Proportional Hazards Models; D018426:SEER Program; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000453:epidemiology; D014481:United States / Q000453:epidemiology