title: Long-term outcomes of (131)Iodine mIBG therapy in metastatic gastrointestinal pancreatic neuroendocrine tumours: single administration predicts non-responders.
abstract: BACKGROUND
  (131)Iodine (I131)-metaiodobenzylguanidine (mIBG) is a radionuclide-based treatment option for metastatic gastrointestinal-pancreatic neuroendocrine tumours (GEP NET). This study aimed at identifying prognostic indicators of long-term outcome based on initial evaluation following a first mIBG treatment (7400 MBq) in a patient cohort with such tumours, with a secondary aim of evaluating progression-free survival (PFS) and overall survival (OS) following mIBG therapy.
  
  
  METHODS
  Retrospective review of the hospital records was performed to identify a cohort of 38 adult patients who underwent (131)Iodine-mIBG therapy over a 9-year period for metastatic GEP NETs and neuroendocrine tumours with an unknown primary. Treatment response was evaluated based on radiological criteria (RECIST1.1), biochemical markers [serum Chromogranin A (CgA)/urinary 5HIAA] and symptomatic response at clinical follow-up, all evaluated at 3-6 months from first mIBG treatment. Progression-free survival (PFS) and overall survival (OS) from the first mIBG treatment were recorded.
  
  
  RESULTS
  At 3-6 months following a single mIBG therapy, 75%, 67%, and 63% of patients showed either a partial response (PR) or stable disease (SD) on radiological, biochemical, and symptomatic criteria, respectively. Complete response (CR) was not seen in any patient. OS from the date of diagnosis and from the first therapy was 8 years +/-1.1 (95% CI 5.7 to 10.2 years) and 4 years+/-0.69 (95% CI 2.6-5.3 years), respectively. Twenty-nine percent of patients were alive at 10 years. Significant survival advantage was seen in patients with SD/PR as compared to those who had progressive disease (PD) for each of these three criteria.
  
  
  CONCLUSIONS
  Biochemical, radiological (RECIST 1.1) and symptomatic assessment of disease status at 3 to 6 months after first I131-mIBG therapy stratifies patients with a poor prognosis. This can be used to identify patients who may benefit from alternative strategies of treatment.
authors.affiliation: Department of Nuclear Medicine, King's College Hospital, Denmark Hill, London, SE5 9RS, UK. nicolamulholland@nhs.net.
authors.forename: Nicola
authors.identifier: http://orcid.org/0000-0003-0912-9890
authors.initials: N
authors.lastname: Mulholland
authors.affiliation: Department of Nuclear Medicine, King's College Hospital, Denmark Hill, London, SE5 9RS, UK.
authors.forename: Riddhika
authors.initials: R
authors.lastname: Chakravartty
authors.affiliation: Department of Nuclear Medicine, King's College Hospital, Denmark Hill, London, SE5 9RS, UK.
authors.forename: Lindsey
authors.initials: L
authors.lastname: Devlin
authors.affiliation: Department of Nuclear Medicine, King's College Hospital, Denmark Hill, London, SE5 9RS, UK.
authors.forename: Eleni
authors.initials: E
authors.lastname: Kalogianni
authors.affiliation: Department of Nuclear Medicine, King's College Hospital, Denmark Hill, London, SE5 9RS, UK.
authors.forename: Ben
authors.initials: B
authors.lastname: Corcoran
authors.affiliation: Department of Nuclear Medicine, King's College Hospital, Denmark Hill, London, SE5 9RS, UK.
authors.forename: Gillian
authors.initials: G
authors.lastname: Vivian
mesh_terms: D019797:3-Iodobenzylguanidine / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D018358:Neuroendocrine Tumors / Q000473:pathology / Q000532:radiotherapy*; D010190:Pancreatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000627:therapeutic use*; D016019:Survival Analysis
chemical_list: D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine
keywords: Carcinoid; I131 mIBG; Metaiodobenzylguanidine; Neuroendocrine tumours; Radionuclide therapy; Risk stratification