Feasibility, toxicity and response of upfront metaiodobenzylguanidine therapy therapy followed by German Pediatric Oncology Group Neuroblastoma 2004 protocol in newly diagnosed stage 4 neuroblastoma patients.

Feasibility, toxicity and response of upfront metaiodobenzylguanidine therapy therapy followed by German Pediatric Oncology Group Neuroblastoma 2004 protocol in newly diagnosed stage 4 neuroblastoma patients.
The primary aim of this German study was to determine the feasibility and toxicity of upfront MIBG therapy followed by a standard high risk protocol in high risk neuroblastoma.
This study is a retrospective, multi-centre analysis of a cohort pilot regimen which included all consecutive newly diagnosed stage 4 neuroblastoma patients. The protocol involved two courses of upfront MIBG therapy, followed by the standard high risk arm of the GPOH NB 2004 protocol (6 courses of induction chemotherapy), followed by surgery. Patients who achieved a response continued on to autologous stem cell transplant followed by radiation to the primary tumor site and retinoic acid. Response rates were assessed post MIBG cycles, post induction chemotherapy and post stem cell transplant.
Upfront MIBG therapy was given to 21 of 32 patients (11/32 were MIBG non-avid). Twenty out of 21 patients received MIBG within two weeks of diagnosis, which was the target for feasibility. Response rate following stem cell transplant was improved for the MIBG group compared to the chemotherapy-only group (71% vs 36%) and was comparable to other MIBG treatment studies.
The main limitation to this study is the fact that it is not a randomized trial, and there was selection bias implicit in the different arms, which was compounded by the small numbers included in the trial.
Upfront MIBG therapy in stage 4 neuroblastoma is feasible, the toxicity is acceptable compared to chemotherapy only regimens and it shows a similar response rate to other MIBG treatment trials; however, there continue to be questions around the optimal time point for the incorporation of MIBG therapy into neuroblastoma treatment protocols.