News from Theragnostics in Children with Neuroblastoma

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Introduction: Neuroblastoma is an embryonal malignancy that affects normal development of the adrenal medulla and paravertebral sympathetic ganglia in early childhood. The standard therapies, depending on the estimated relapsed risk, consist of intensive multimodal chemotherapy, surgery, radiation therapy, and high-dose chemotherapy with ASCT. In addition, 90% of neuroblastomas show high mIBG avidity due to presence of NE transporters that represent a molecular target for both imaging diagnostics and therapeutics, i.e., a theragnostics target. ¹³¹I mIBG therapy can be helpful as part of curative strategy in combination with chemotherapy, radiosensitizer (Topotecan), and ASCT in patients with high-risk disease or as palliative treatment for end stage disease. The aim of this study was to assess the efficacy and safety of ¹³¹I mIBG high-activity therapy in combination with Topotecan in patients with ¹²³I mIBG-positive, high-risk neuroblastoma.

Methods: This is a retrospective study of the outcome of 15 patients with high-risk neuroblastoma (7 female, 8 male, age between 2 and 16 years) treated with high-activity ¹³¹I mIBG to achieve 4 Gy total body absorbed doses in combination with Topotecan. Administrated activity ranged between 5.3 and 24.65 GBq ¹³¹I-mIBG and treatment response was evaluated by comparing CT or MRI and ¹²³I-mIBG-scan before therapy with those obtained 2 months after therapy.

Results: Eight patients are still alive (1 of them treated in 2009), 7 patients died between 3 and 48 months after therapy, progressive disease was observed in 2 patients, partial remission in 8 patients, stable disease in 3 patients and complete remission in 2 patients. For what concern side effects, no symptoms related to catecholamine excretion were observed. Fever was observed in 7 patients, hypothyroidism in 4 patients, mucositis in 3 patients, neutropenia in all patients, and grade 4 thrombocytopenia in 3 patients.

Conclusion: High-activity ¹³¹I-MIBG therapy combined with Topotecan and ASCT is effective, safe, and well tolerated due to no fatal toxicity observed. This therapy may improve outcome in patients with refractory disease. In terms of feasibility, this therapy approach needs a multidisciplinary team, requiring support from nuclear medicine, pediatricians, and a physicist.

Publication History

Article published online:
25 May 2023