title: Correlation of early metastatic response by 123I-metaiodobenzylguanidine scintigraphy with overall response and event-free survival in stage IV neuroblastoma.
abstract: OBJECTIVE
  Metaiodobenzylguanidine (MIBG), specifically taken up in cells of sympathetic origin, provides a highly sensitive and specific indicator for the detection of metastases in neuroblastoma. The aim of this study was to correlate early response to therapy by MIBG scan, using a semiquantitative scoring method, with the end induction response and event-free survival (EFS) rate in stage IV neuroblastoma.
  
  
  METHODS
  Seventy-five children older than 1 year and with stage IV neuroblastoma had 123I-MIBG scans at diagnosis, after two and four cycles of induction therapy, and before autologous stem-cell transplantation. The scans were read by two independent observers (concordance > 95%) using a semiquantitative method. Absolute and relative (score divided by initial score) MIBG scores were then correlated with overall pretransplantation response, bone marrow response, and EFS.
  
  
  RESULTS
  The pretransplantation response rate was 81%, and the 3-year EFS rate was 32%, similar to a concomitant group of 375 stage IV patients. The median relative MIBG scores after two, four, and six cycles were 0.5, 0.24, and 0.12, respectively. The probability of having a complete response or very good partial response before transplantation was significantly higher if the relative score after two cycles was < or = 0.5, or, if after four cycles, the relative score was < or = 0.24. Patients with a relative score of < or = 0.5 after two cycles or a score of < or = 0.24 after four cycles had an improved EFS rate (P =.053 and.045, respectively).
  
  
  CONCLUSIONS
  Semiquantitative MIBG score early in therapy provides valuable prognostic information for overall response and EFS, which may be useful in tailoring treatment.
authors.affiliation: Department of Pediatrics, University of California School of Medicine, San Francisco 94143-0106, USA. matthayk@peds.ucsf.edu
authors.forename: Katherine K
authors.initials: KK
authors.lastname: Matthay
authors.forename: Veronique
authors.initials: V
authors.lastname: Edeline
authors.forename: Jean
authors.initials: J
authors.lastname: Lumbroso
authors.forename: Marie Laure
authors.initials: ML
authors.lastname: Tanguy
authors.forename: Bernard
authors.initials: B
authors.lastname: Asselain
authors.forename: Jean Michel
authors.initials: JM
authors.lastname: Zucker
authors.forename: Dominique
authors.initials: D
authors.lastname: Valteau-Couanet
authors.forename: Olivier
authors.initials: O
authors.lastname: Hartmann
authors.forename: Jean
authors.initials: J
authors.lastname: Michon
mesh_terms: D019797:3-Iodobenzylguanidine; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007223:Infant; D007457:Iodine Radioisotopes; D008297:Male; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging*; D009447:Neuroblastoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D010347:Patient Care Planning; D036102:Peripheral Blood Stem Cell Transplantation; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine