title: Prevalence and clinical features of the ectopic ACTH syndrome in patients with gastroenteropancreatic and thoracic neuroendocrine tumors.
abstract: OBJECTIVE
  Several series report on the relative contribution of ectopic ACTH syndrome (EAS) in the spectrum of Cushing's syndrome. However, prevalence of EAS in patients with thoracic or gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is currently unknown.
  
  
  METHODS
  We assessed, in a tertiary referral center, the prevalence of EAS in a large cohort of thoracic and GEP-NET patients including clinical, biochemical, and radiological features; management; and treatment outcome.
  
  
  METHODS
  In total, 918 patients with thoracic or GEP-NETs were studied (1993-2012). Multiple endocrine neoplasia type 1 and small cell lung carcinoma patients were excluded. Differentiation between synchronous, metachronous, and cyclic occurrence of EAS was made.
  
  
  RESULTS
  Out of the 918 patients with thoracic and GEP-NETs (469 males and 449 females; median age 58.7 years (range: 17.3-87.3)), 29 patients (3.2%) had EAS (ten males and 19 females; median age 48.1 years (range: 24.7-77.9)). EAS occurred synchronously in 23 patients (79%), metachronously in four patients (14%), and cyclical in two patients (7%) respectively. NETs causing EAS included lung/bronchus (n=9), pancreatic (n=9), and thymic (n=4). In four patients, the cause of EAS was unknown (n=4). Median overall survival (OS) of non-EAS thoracic and GEP-NET patients was 61.2 months (range: 0.6-249.4). Median OS of EAS patients was 41.4 months (range: 2.2-250.9). After comparison, only the first 5-year survival was significantly shorter (P=0.013) in EAS patients.
  
  
  CONCLUSIONS
  Prevalence of EAS in this large cohort of patients with thoracic and GEP-NETs was 3.2%. EAS was mostly caused by thoracic and pancreatic NETs. First 5-year survival of EAS patients was shorter compared with non-EAS patients.
authors.affiliation: Sector of EndocrinologyDepartment of Internal MedicineDepartment of PathologyDepartment of Surgery, ENETS Center of Excellence, Erasmus Medical Center's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands k.kamp@erasmusmc.nl.
authors.forename: K
authors.initials: K
authors.lastname: Kamp
authors.affiliation: Sector of EndocrinologyDepartment of Internal MedicineDepartment of PathologyDepartment of Surgery, ENETS Center of Excellence, Erasmus Medical Center's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: R A
authors.initials: RA
authors.lastname: Alwani
authors.affiliation: Sector of EndocrinologyDepartment of Internal MedicineDepartment of PathologyDepartment of Surgery, ENETS Center of Excellence, Erasmus Medical Center's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Korpershoek
authors.affiliation: Sector of EndocrinologyDepartment of Internal MedicineDepartment of PathologyDepartment of Surgery, ENETS Center of Excellence, Erasmus Medical Center's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: G J H
authors.initials: GJ
authors.lastname: Franssen
authors.affiliation: Sector of EndocrinologyDepartment of Internal MedicineDepartment of PathologyDepartment of Surgery, ENETS Center of Excellence, Erasmus Medical Center's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: W W
authors.initials: WW
authors.lastname: de Herder
authors.affiliation: Sector of EndocrinologyDepartment of Internal MedicineDepartment of PathologyDepartment of Surgery, ENETS Center of Excellence, Erasmus Medical Center's-Gravendijkwal 230, 3015 CE Rotterdam, The Netherlands.
authors.forename: R A
authors.initials: RA
authors.lastname: Feelders
mesh_terms: D000182:ACTH Syndrome, Ectopic / Q000175:diagnosis / Q000453:epidemiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000453:epidemiology*; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D015995:Prevalence; D011379:Prognosis; D012189:Retrospective Studies; D062606:Tertiary Care Centers; D013953:Thymus Neoplasms / Q000175:diagnosis / Q000453:epidemiology*; D055815:Young Adult