Comparison of Fixed versus Calculated Activity of Radioiodine for the Treatment of Graves Disease in Adults.

BACKGROUND: Radioactive iodine as a treatment modality has been shown in several studies to be a safe and effective therapy for Graves disease. However, there is still no uniformity regarding optimal dosing method. The aim of this study is to compare the efficacy of calculated and fixed dosing of radioiodine for the treatment of Graves disease. METHODS: A hundred twenty-two patients diagnosed with Graves disease were randomized to receive either fixed or calculated dose of radioiodine. Those randomized to fixed activity received either low fixed activity at 9.9 mCi for thyroid gland size <40 g or high fixed activity at 14.9 mCi for thyroid gland size 40 to 80 g, and those grouped to calculated activity received 160 µCi/g of thyroid tissue adjusted for 24 hours radioiodine uptake. Thyroid function tests (free thyroxine [T4] and thyroid stimulating hormone [TSH]) were monitored at 10, 16, and 24 weeks after radioactive iodine therapy. The primary outcome, treatment failure was defined as persistently elevated free T4 and low TSH. RESULTS: Of the 122 patients randomized, 56 in the fixed dose group and 56 in the calculated dose group completed the follow-up. At the end of 6 months, the percentage of treatment failure was 37.50% in the calculated dose group versus 19.64% in the fixed dose group with a relative risk of 0.53 (95% confidence interval, 0.28 to 0.98) favoring the fixed dose group. CONCLUSION: Fixed dose radioiodine has a significantly lower incidence of persistent hyperthyroidism at 6 months post-radioactive therapy.

International Atomic Energy Agency-sponsored multination study of intra-arterial rhenium-188-labeled lipiodol in the treatment of inoperable hepatocellular carcinoma: results with special emphasis on prognostic value of dosimetric study.

A multicenter study was sponsored by the International Atomic Energy Agency (IAEA) to assess the safety and efficacy of transarterial rhenium-188 ((188)Re) HDD lipiodol (radioconjugate to lipiodol using an HDD kit) in the treatment of unresectable hepatocellular carcinoma. During 5 years, 185 patients received at least 1 treatment of radioconjugate, and 51 were retreated. The level of radioconjugate administered was based on radiation-absorbed dose to critical normal organs, calculated after a "scout" dose of radioconjugate. The total injected activity, including the scout dose during the first treatment, ranged from 21 to 364 mCi (mean, 108 mCi/4 GBq). Immediate and late side-effects were minimal. Tumor size could be evaluated in 88 patients. Among these patients, the objective response rate was 25%; stable disease was observed in 53% and tumor progression in 22%. With a median follow-up of 455 days, the estimated 12- and 24-month overall survival was 46% and 23%. This multicenter study shows that (188)Re lipiodol is a safe and cost-effective method to treat primary hepatocellular carcinoma via the transarterial route and requires further evaluation by treatment of greater numbers of patients.

Intra-arterial rhenium-188 lipiodol in the treatment of inoperable hepatocellular carcinoma: results of an IAEA-sponsored multination study.

PURPOSE: Intra-arterial injections (IAI) of 131I-lipiodol is effective in treating hepatocellular carcinoma patients, but is expensive and requires a 7-day hospitalization in a radioprotection room. 188Re is inexpensive, requires no patient isolation, and can be used with lipiodol. METHODS AND MATERIALS: This International Atomic Energy Agency-sponsored phase II trial aimed to assess the safety and the efficacy of a radioconjugate 188Re + lipiodol (188Re-Lip) in a large cohort of hepatocellular carcinoma patients from developing countries. A scout dose is used to determine the maximal tolerated dose (lungs <12 Gy, normal liver <30 Gy, bone marrow <1.5 Gy) and then the delivery of the calculated activity. Efficacy was assessed using response evaluation criteria in solid tumor (RECIST) and alpha-feto-protein (alpha FP) levels and severe adverse events were graded using the Common Toxicity Criteria of the National Cancer Institute scale v2.0. RESULTS: The trial included 185 patients from eight countries. The procedure was feasible in all participating centers. One treatment was given to 134 patients; 42, 8, and 1 received two, three, and four injections, respectively. The injected activity during the first treatment was 100 mCi. Tolerance was excellent. We observed three complete responses and 19 partial responses (22% of evaluable patients, 95% confidence interval 16-35%); 1- and 2-year survivals were 46% and 23%. Some factors affected survival: country of origin, existence of a cirrhosis, Cancer of the Liver Italian Program score, tumor dose, absence of progression, and posttreatment decrease in alpha FP level. CONCLUSIONS: IAI of 188Re-Lip in developing countries is feasible, safe, cost-effective, and deserves a phase III trial.