Comparison of 123I-Metaiodobenzylguanidine (MIBG) and 131I-MIBG Semi-Quantitative Scores in Predicting Survival in Patients With Stage 4 Neuroblastoma: A Report From the Children's Oncology Group

Background. I-123-metaiodobenzylguanidine (MIBG) scans are preferable to I-131-MIBG for neuroblastoma imaging as they deliver less patient radiation yet have greater sensitivity in disease detection. Both I-123-MIBG and I-131-MIBGscans were used for disease assessments of neuroblastoma patients enrolled on Children's Oncology Group (COG) high-risk study A3973. The hypothesis was that I-123-MIBG and I-131-MIBGscans were sufficiently similar for clinical purposes in terms of ability to predict survival. Procedure. Patients enrolled on COG A3973 with stage 4 disease who completed I-123-MIBG or I-131-MIBGscans at diagnosis, post-induction, posttransplant, or post-biotherapy were analyzed. The performance of the Curie score for each MIBG scan type in predicting survival was evaluated. At each time point, survival curves for I-123-MIBG versus I-131-MIBGwere compared using the log-rank test. Results. Of the 413 patients on A3973 with at least one MIBG scan, 350 were stage 4. The 5-year event-free survival (EFS) and overall survival (OS) rates were 33.4 +/- 3.6% and 45.6 +/- 4.0% (N = 350). At post-induction, EFS (P = 0.3501) and OS (P = 0.5337) for I-123-MIBG versus I-131-MIBGwere not significantly different. Similarly, comparisons at the three other time points were non-significant. Conclusions. We found no evidence of a statistically significant difference in outcome by type of scan. For future survival analyses of MIBG Curie scores, I-123-MIBG and I-131-MIBGresults may be combined and analyzed overall, without adjustment for scan type. Pediatr Blood Cancer 2011; 56: 1041-1045. (C) 2011 Wiley-Liss, Inc.