title: A Comparison Between Appendiceal and Nonappendiceal Neuroendocrine Tumors in Children and Young Adults: A Single-institution Experience.
abstract: BACKGROUND
  Pediatric neuroendocrine tumors (NETs) are rare tumors. The purpose of this study is to report the clinical characteristics and outcomes of pediatric patients treated for NET at a single institution.
  
  
  METHODS
  A retrospective record review.
  
  
  RESULTS
  There were 33 evaluable patients with median age of 17.9 years (range, 9.9 to 21.9 y) and predominantly females (58%). There were 17 patients with well-differentiated appendiceal NET, whereas 16 were nonappendiceal. Most common nonappendiceal sites were unknown primary (N=6) and pancreas (N=4). Majority of tumors were low grade (N=24, 73%) and small (T1, N=22, 67%). Nonappendiceal tumors were more likely to be larger or high-grade tumors (5/16, 31%), or with metastasis. All appendiceal NET patients underwent curative surgery. All patients who experienced treatment failure had nonappendiceal NET, despite prior chemotherapy in 8 of 9 patients. The 5-year overall survival rates for patients with appendiceal and nonappendiceal NET were 100% and 66% (95% CI, 45%-95%; P=0.006); and 5-year relapse-free survival rate for patients with appendiceal and nonappendiceal NET were 100% and 41% (95% CI, 22%-75%; P=0.002).
  
  
  CONCLUSIONS
  Well-differentiated appendiceal tumors were the most common pediatric NET and have an excellent prognosis. Better therapies are needed for patients with nonappendiceal NET.
authors.affiliation: *Division of Pediatrics ‡Department of Biostatistics, The University of Texas MD Anderson Cancer Center †Department of Gastrointestinal Medical Oncology, Methodist Hospital, Houston, TX.
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Boston
authors.forename: Alexandria
authors.initials: A
authors.lastname: Phan
authors.forename: Mark F
authors.initials: MF
authors.lastname: Munsell
authors.forename: Cynthia E
authors.initials: CE
authors.lastname: Herzog
authors.forename: Winston W
authors.initials: WW
authors.lastname: Huh
mesh_terms: D000293:Adolescent; D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001063:Appendiceal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D055815:Young Adult