title: Varying malignant potential of appendiceal neuroendocrine tumors: importance of histologic subtype.
abstract: BACKGROUND
  Neuroendocrine tumors (NETs) of the appendix include malignant carcinoid tumor (MCT), goblet cell carcinoid (GCT), and composite goblet cell carcinoid-adenocarcinoma (CGCC-A).
  
  
  METHODS
  We compared characteristics and outcomes of these histologic subtypes. Patients with appendiceal NETs were identified from the National Cancer Database (1998-2007). Descriptive statistics were used to compare cohorts and associations between clinicopathologic factors and overall survival (OS) were examined using Cox proportional hazards models.
  
  
  RESULTS
  A total of 2,812 patients with appendiceal NETs were identified. The most common histologic subtype was GCT (59.6%), followed by MCT (32.1%), CGCC-A (6.9%), and others (1.4%). CGCC-A had a significantly higher incidence of lymph node metastases (odds ratio [OR], 3.2; 95% confidence interval [CI], 2.1-4.8) and distant metastases (OR, 6.0; 95% CI = 3.8-9.3) than GCT. The 5-year OS was 86.3% (95% CI, 81.4-89.9) for MCT, 77.6% (95% CI, 74.0-80.8) for GCT, and 56.3% (95% CI, 42.1-68.4) for CGCC-A (P < 0.0001).
  
  
  CONCLUSIONS
  Appendiceal NETs represent a spectrum of disease with varying malignant potential: MCT (low), GCT (intermediate), and CGCC-A (high). GCTs represent the most common subtype, whereas CGCC-As place the patient at highest risk for regional and distant metastases and have the worst prognosis.
authors: Department of Surgical Oncology and Cancer Surgical Outcomes Group, The University of Texas, MD Anderson Cancer Center, Houston, TX 77030-1402, USA.
authors: Cary
authors: C
authors: Hsu
authors: Asif
authors: A
authors: Rashid
authors: Yan
authors: Y
authors: Xing
authors: Yi-Ju
authors: YJ
authors: Chiang
authors: Ryaz B
authors: RB
authors: Chagpar
authors: Keith F
authors: KF
authors: Fournier
authors: George J
authors: GJ
authors: Chang
authors: Y Nancy
authors: YN
authors: You
authors: Barry W
authors: BW
authors: Feig
authors: Janice N
authors: JN
authors: Cormier
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001063:Appendiceal Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D002276:Carcinoid Tumor / Q000175:diagnosis / Q000401:mortality / Q000473:pathology / Q000628:therapy; D003131:Combined Modality Therapy; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D018193:Neoplasms, Complex and Mixed / Q000175:diagnosis / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D018358:Neuroendocrine Tumors / Q000175:diagnosis / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D011379:Prognosis; D016019:Survival Analysis