The role of ¹³¹I-metaiodobenzylguanidine (MIBG) therapy in unresectable and compromising localised neuroblastoma

Purpose: In patients with localised neuroblastoma without adverse genetic aberrations, observational treatment is justified. Therapy is required when organ or respiratory functions have become compromised. As the outcome is good, side effects of treatment should be prevented. The aim of this retrospective study was to evaluate response and outcome in patients treated with ¹³¹I-metaiodobenzylguanidine (MIBG) for unresectable localised neuroblastoma, with compromised organ functions. Methods: Patients with localised neuroblastoma [median age 1.6 years (0-5.5 years)] diagnosed between 1989 and 2008 were included in this retrospective study (n=21). Primary tumours were unresectable and there was a compromised organ or respiratory function. Diagnosis and staging were performed according to the International Neuroblastoma Staging System. Fixed doses of ¹³¹I-MIBG therapy (50-200 mCi) were given. The median number of infusions was two (range one to seven). Response was graded according to the International Neuroblastoma Response Criteria. Results: Of the 21 patients, 14 did not need any chemotherapy. Patients were treated with ¹³¹I-MIBG therapy and, in most cases, with additional surgery and/or chemotherapy. Sixteen achieved complete response (CR), three very good partial response (VGPR), one partial response (PR) and one progressive disease (PD). Two patients died of PD after having achieved CR initially and due to surgical complications a few months after resection. Ten-year overall survival and event-free survival were 90.5 %. The median follow-up was 8.5 years (range 0.4-19.6 years). Conclusion: ¹³¹I-MIBG therapy is an effective treatment modality for unresectable localised neuroblastoma with compromised organ functions. However, this was a small and heterogeneous cohort and further studies are needed.