Correlation of early metastatic response by 123I-metaiodobenzylguanidine scintigraphy with overall response and event-free survival in stage IV neuroblastoma.
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.
Matthay
Katherine K
KK
Department of Pediatrics, University of California School of Medicine, San Francisco 94143-0106, USA. matthayk@peds.ucsf.edu
Edeline
Veronique
V
Lumbroso
Jean
J
Tanguy
Marie Laure
ML
Asselain
Bernard
B
Zucker
Jean Michel
JM
Valteau-Couanet
Dominique
D
Hartmann
Olivier
O
Michon
Jean
J
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
D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine