title: Efficacy of using a standard activity of (131)I-MIBG therapy in patients with disseminated neuroendocrine tumours.
abstract: OBJECTIVE
  The aim of this analysis was to evaluate the response to standard activity of (131)I-meta-iodobenzylguanidine (MIBG) in patients with disseminated neuroendocrine tumours (NETs), comparing overall survival of patients with symptomatic response, tumour size (as assessed by CT) and relevant plasma tumour markers.
  
  
  METHODS
  A retrospective review of patients who had undergone (131)I-MIBG treatment between March 2001 and December 2006 was carried out. The administered activity of (131)I-MIBG was 5.5 GBq (NETs) and 7 GBq (phaeochromocytoma). Three cycles of treatment were planned with an interval of 10-12 weeks. A pre-therapy scan with (123)I-MIBG was performed to ascertain appropriate biodistribution.
  
  
  RESULTS
  Thirty-eight patients were identified. Only two patients developed significant bone marrow suppression. Symptomatic response: data were available in 37 of 38 patients: 15 patients had improved symptoms, 19 had no improvement in symptoms and 3 were asymptomatic. In those with a symptomatic response, the median overall survival was 58 months vs no response of 20.0 months (p = 0.001). CT response: in those with stable disease, the median overall survival was 58 months compared with progressive disease of 16.0 months. The difference between these groups was significant (p = 0.006). Hormonal response: this was available in only 20 of 38 patients. The median overall survival was the same for patients that had increased hormone levels and patients that had stable/decreased hormone levels (48 months).
  
  
  CONCLUSIONS
  Standard activity (131)I-MIBG is well tolerated. Symptomatic response to treatment is a significant predictor of overall survival. Whilst CT response also appears to predict survival, hormonal levels do not appear to correlate with survival.
authors.affiliation: Department of Nuclear Medicine, Royal Free Hospital, London, NW3 2QG, UK. shaunakn@hotmail.com
authors.forename: Shaunak
authors.initials: S
authors.lastname: Navalkissoor
authors.forename: Dona M
authors.initials: DM
authors.lastname: Alhashimi
authors.forename: Ann-Marie
authors.initials: AM
authors.lastname: Quigley
authors.forename: Martyn E
authors.initials: ME
authors.lastname: Caplin
authors.forename: John R
authors.initials: JR
authors.lastname: Buscombe
mesh_terms: D019797:3-Iodobenzylguanidine / Q000009:adverse effects / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000097:blood; D018450:Disease Progression; D005260:Female; D006728:Hormones / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology / Q000532:radiotherapy*; D019275:Radiopharmaceuticals / Q000009:adverse effects / Q000627:therapeutic use*; D012189:Retrospective Studies; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor; D006728:Hormones; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine