title: Identification of primary tumors in patients presenting with metastatic gastroenteropancreatic neuroendocrine tumors.
abstract: Patients with gastroenteropancreatic neuroendocrine tumors often present with metastases. Identification of the primary tumor is important for operative management, and therefore we sought to determine our success at identifying primary tumors with diagnostic testing and operative exploration.
  
  
  
  A clinical neuroendocrine tumor database was reviewed to identify patients presenting with metastases and primary tumor in situ. Results of radiologic, endoscopic, and operative procedures were evaluated to determine which correctly identified the primary tumor.
  
  
  
  There were 197 patients presenting with metastases and unresected primaries, 134 who had an operation and 63 managed nonoperatively. Primaries were identified preoperatively in 168 (84%), at operative exploration in 7, and were not found in 22 patients. Computed tomography found 150/197 primary tumors, somatostatin-receptor scintigraphy 88/155, and endoscopy 43/107. The sensitivity of computed tomography surpassed scintigraphy (76% vs 57%, P < .01). The primary was removed in 130/134 (97%) patients, and hepatic debulking was performed in 67%. Median survival for operative patients with small bowel and pancreatic tumors was 145 and 71 months, respectively.
  
  
  
  Imaging and endoscopy identified the primary tumor in most patients, and the majority of the others were found at exploration. Preoperative testing facilitated operative planning, allowing for resection of the primary and hepatic debulking in most patients.
authors.affiliation: Department of Surgery, University of Iowa Carver College of Medicine, Iowa City, IA.
authors.forename: Kendall J
authors.initials: KJ
authors.lastname: Keck
authors.affiliation: Department of Surgery, University of Iowa Carver College of Medicine, Iowa City, IA.
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Maxwell
authors.affiliation: Department of Radiology, University of Iowa Carver College of Medicine, Iowa City, IA.
authors.forename: Yusuf
authors.initials: Y
authors.lastname: Menda
authors.affiliation: Department of Pathology, University of Iowa Carver College of Medicine, Iowa City, IA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Bellizzi
authors.affiliation: Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Dillon
authors.affiliation: Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, IA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: O'Dorisio
authors.affiliation: Department of Surgery, University of Iowa Carver College of Medicine, Iowa City, IA. Electronic address: james-howe@uiowa.edu.
authors.forename: James R
authors.initials: JR
authors.lastname: Howe
mesh_terms: D000328:Adult; D016208:Databases, Factual; D018572:Disease-Free Survival; D016145:Endoscopy, Digestive System / Q000379:methods; D019160:Endosonography / Q000379:methods; D005260:Female; D006801:Humans; D007414:Intestinal Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D007813:Laparotomy / Q000379:methods; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging / Q000473:pathology; D009367:Neoplasm Staging; D009382:Neoplasms, Unknown Primary / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome