Repeated Radionuclide therapy in metastatic paraganglioma leading to the highest reported cumulative activity of ¹³¹I-MIBG

¹³¹I-MIBG therapy for neuroendocrine tumours may be dose limited. The common range of applied cumulative activities is 10-40 GBq. We report the uneventful cumulative administration of 111 GBq (= 3 Ci) ¹³¹I-MIBG in a patient with metastatic paraganglioma. Ten courses of ¹³¹I-MIBG therapy were given within six years, accomplishing symptomatic, hormonal and tumour responses with no serious adverse effects. Chemotherapy with cisplatin/vinblastine/dacarbazine was the final treatment modality with temporary control of disease, but eventually the patient died of progression. The observed cumulative activity of ¹³¹I-MIBG represents the highest value reported to our knowledge, and even though 12.6 GBq of ⁹⁰Y-DOTATOC were added intermediately, no associated relevant bone marrow, hepatic or other toxicity were observed. In an individual attempt to palliate metastatic disease high cumulative activity alone should not preclude the patient from repeat treatment.