Therapy of malignant paraganglioma with 131I MlBG.
The anterior view (a) of the thorax shows multiple sites of abnormal uptake in the upper mediastinum before therapy. During a course of therapy (b): after a total of two doses of 8.9GBq (240mCi) of N MIBG, six months later (T: mediastinal tumour arrow; lung metastasis: Ad; adrenal medulla). Image (c) taken after a total of approximately 37GBq (1Ci) of 131I MIBG, five years later. The reduction in uptake is evident. Before therapy, this patient was incapacitated with symptoms and could not work. After therapy he resumed full-time work, was taken off of all drugs and has fathered three healthy children. In malignant phaeochromocytoma, paraganglioma and some metastatic carcinoids a good clinical and biochemical response is seen after 131I MIBG therapy. There is usually reduction of active tumour mass observed on CT. There may be residual sites of uptake seen even though the patient is asymptomatic and catecholamine levels are normal. As the cell turnover in such tumours is slow, so is the interval to response. Thus, benefit may not be clearly established until more than nine months have passed and, therefore, a course of treatment must be planned.
