title: [131I]metaiodobenzylguanidine therapy of malignant pheochromocytoma: interference of medication.
abstract: Malignant pheochromocytoma may present as a widespread metastatic disease, which is little or non-responsive to external beam radiotherapy and chemotherapy. The prognosis of these patients is bad due to both the progressive metastasis and the secretion of excess catecholamines which may cause hypertensive episodes. For these conditions [131I]metaiodobenzylguanidine (131I-MIBG) therapy may be an alternative treatment modality to induce both tumor remission and reduction of hormonal activity of the disease. The experience with 131I-MIBG therapy in four patients with metastatic malignant pheochromocytoma at The Netherlands Cancer Institute is reviewed. One patient with abdominal tumor recurrence and metastases to the lymph nodes and lungs had a partial remission of disease for 3 years; a second had a mixed response together with palliation and two other patients had stable disease, but were relieved of bone pain and severe hypertension, respectively. It is essential to be aware of the medication the patient is using, as many drugs are known or may be expected to interfere with the uptake and/or retention of 131I-MIBG by the tumor cells. The case of a significant reduction of 131I-MIBG uptake and retention by Labetalol in one of the patients is discussed. It is concluded that 131I-MIBG therapy may induce objective remission in patients with malignant pheochromocytoma and is certainly meaningful in the reduction of hormonal activity, the control of hypertension and the relief of pain from metastases.
authors.affiliation: Department of Nuclear Medicine, The Netherlands Cancer Institute, Amsterdam.
authors.forename: C A
authors.initials: CA
authors.lastname: Hoefnagel
authors.forename: J
authors.initials: J
authors.lastname: Schornagel
authors.forename: R A
authors.initials: RA
authors.lastname: Valdés Olmos
mesh_terms: D019797:3-Iodobenzylguanidine; D000310:Adrenal Gland Neoplasms / Q000628:therapy*; D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D004347:Drug Interactions; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D007462:Iodobenzenes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010673:Pheochromocytoma / Q000556:secondary* / Q000628:therapy
chemical_list: D000970:Antineoplastic Agents; D007457:Iodine Radioisotopes; D007462:Iodobenzenes; D019797:3-Iodobenzylguanidine