ABSTRACT
Objective To evaluate the efficacy and safety of 131I-metaiodobenzylguanidine (131 I-MIBG) in treatment of malignant pheochromocytoma/malignant paraganglioma (MPHEO/MPGL).Methods The clinical data of 96 cases of MPHEO/MPGL (60/36) treated with 131I-MIBG between December 1998 and April 2014 were retrospectively reviewed.Among them,the malignant pheochromocytoma was found in 60 cases and malignant paraganglioma was found in 36 cases.Seventy-eight patients (81.2％)presented initially with hypertension,whereas 18 patients (18.8％) presented adrenal incidentaloma.Before 131I-MIBG treatment,24 h urinary norepinephrine was (409.5± 127.2) nmol,24 h urinary dopamine was (99.3±41.1) nmol,24 h urine adrenaline was (1 409.9±336.0) nmol.Before treatment,the compound iodine solution was given to each one.Then,all patients were given an initial course of 131I-MIBG therapy (5.55,7.40 GBq).Subsequent 131I-MIBG treatment (5.55,7.40 GBq) was undertaken every three to six months.The patients got symptomatic,hormonal or radiological response underwent sbsequent 131I-MIBG therapy (3.70,5.55 GBq) every year.All patients underwent clinical symptoms (headache,palpitate,sweating,hypertension),biochemical (24 h urine catecholamin) and radiological evaluation (CT/MRI) within 6 months to evaluate the efficacy and safety of 131I-MIBG treatment.Results After one to eleven sessions of 131 I-MIBG treatment,in total,266 doses of 131 I-MIBG were administered,average dose was 6.49 GBq.22.9％ of patients demonstrated radiological partial response (≥ 50％ reduction in tumor size) after first or repeated 131 I-MIBG treatment.Eleven cases (11.5％) achieved clinical complete response,41 cases (42.7％) achieved clinical partial response and 23 cases (24.0％) maintained the stable clinic symptoms.After treatment,24 h urinary norepinephrine (164.3±71.6) nmol and dopamine (49.7±24.7) nmol showed significantly decline,compared with those before treatment (P＜ 0.05).While,24 h urinary epinephrine (1 354.7±433.4) nmol had no obvious change (P＞0.05).No life-threatening adverse events were reported,but 2 MPGL patients developed transient leucopenia or thrombocytopenia after four and five times 131 I-MIBG treatment,respectively.Conclusions Treatment with repeated low dose 131I-MIBG is well tolerated and effective in controlling the progression and alleviating the clinical symptoms.The 131I-MIBG therapy is an effective and safe treatment modality for MPHEO/MPGL.