Aim: To evaluate the response of [¹³¹I] metaiodobenzylguanidine ([¹³¹I]MIBG) therapy in patients with neuroectodermal tumors and to assess their quality of life using the functional assessment of cancer therapy - general quality-of-life questionnaire for patients who are on follow-up after MIBG therapy.
Materials and methods: Thirty-two patients diagnosed with various subtypes of neuroectodermal tumors and treated with [¹³¹I]MIBG were included in this retrospective analysis. Response to therapy was evaluated objectively by comparing pretherapy and posttherapy biochemical markers, radiological investigations, and follow-up MIBG scans. Symptomatic response and quality of life were also evaluated in the follow-up visits.
Results: In seven patients with stage III neuroblastoma, an objective response rate was seen in 57% and a symptomatic response rate was seen in 29% of the patients. Among 11 patients with stage IV neuroblastoma, an objective response was observed in 36% and a symptomatic response in 36% of the patients. Among 12 patients with pheochomocytoma and paraganglioma, an objective response was noticed in 8%, but symptomatic improvement and stabilization of disease were seen in 75% of the patients belonging to this category. One patient with medullary carcinoma of the thyroid and one patient with mediastinal carcinoid did not show an objective response but had a stable disease; both patients showed symptomatic improvement. Quality of life has improved in all 11 patients who are still on follow-up.
Conclusion: [¹³¹I]MIBG therapy can be of significant value in the treatment of patients with chemotherapy-resistant stage III and IV neuroblastomas who demonstrate good tracer uptake in diagnostic scans. MIBG therapy has the potential to stabilize the disease and provide symptomatic improvement in patients with metastatic/recurrent pheochomocytoma/paraganglioma and medullary carcinoma thyroid and carcinoid in which there is evidence of tracer accumulation in the tumor. Both single high dose or multiple fractionated doses are equally effective in improving the quality of life in metastatic/recurrent pheochomocytoma/paraganglioma.