title: Medical treatment of neuroendocrine tumors.
abstract: BACKGROUND
  Tumors of the neuroendocrine system are characterized by amine precursor uptake and decarboxylation, and they represent a heterogeneous group of carcinomas including carcinoids, islet cell carcinomas of the pancreas, medullary thyroid carcinomas and Merkel cell carcinomas. Their similar cytochemical and ultrastructural properties sustain the hypothesis of a common embryologic origin within the neural crest. Many of these tumors grow slowly, and reducing tumor burden represents the treatment of choice. However, when surgery is not feasible, medical treatment has to be considered. Therapeutic approaches in metastatic disease often do not consider the different biologic behaviors of these neoplasms. Moreover, efficacy of the treatment is associated with lack of a clear definition of the type of response: objective, symptomatic or biochemical.
  
  
  METHODS
  In this review we have analyzed the different medical approaches used in the treatment of neuroendocrine tumors in an attempt to define their precise role in the different neoplasms.
  
  
  RESULTS
  In carcinoid tumors, immunotherapy and the somatostatin analogue can be efficaciously used for the control of carcinoid syndrome. For inhibition of tumor growth, chemotherapy should be used only in patients with rapidly progressive disease, and the results are still unsatisfactory.
  
  
  CONCLUSIONS
  Although all these tumors appear to have similar cytochemical properties, the responsiveness of the various neoplasms is very different. In the future, a specific treatment modality and a clear definition of the type of response (objective, symptomatic or biochemical) need to be defined for each type of neuroendocrine tumor.
authors.affiliation: Division of Medical Oncology B, Istituto Nazionale per lo Studioe la Cura dei Tumori, Milano, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Bajetta
authors.forename: M
authors.initials: M
authors.lastname: Di Bartolomeo
authors.forename: N
authors.initials: N
authors.lastname: Zilembo
authors.forename: A M
authors.initials: AM
authors.lastname: Bochicchio
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D006801:Humans; D007167:Immunotherapy; D016898:Interferon-alpha / Q000627:therapeutic use; D018358:Neuroendocrine Tumors / Q000188:drug therapy / Q000628:therapy*
chemical_list: D016898:Interferon-alpha