[Evaluation of radioiodine 131I treatment in Graves' disease patients with mild orbitopathy].

UNLABELLED: Radioiodine (131I) treatment of patients with Graves-Basedow disease may cause or aggravate the course of orbitopathy (GO) in some 15% of patients; while only 3% of patients treated with methimazole develop GO. The aim of this study was to evaluate the frequency of GO progression in patients with mild GO treated with 131I, compared to a control group. MATERIALS AND METHODS: The studied group consisted of 21 hyperthyroid patients (mean age 49 +/- 12.8 years) with mild orbitopathy (CAS < 3 pts, NOSPECS < 4 pts). The control group included 18 hyperthyroid patients with Graves-Basedow disease (mean age 50 +/- 9.9 years) with no GO symptoms (CAS = 0 pts, NOSPECS < 1 pts). All patients were treated with 131I. Patients with GO underwent treatment with oral methyloprednisolone (MP) over 30 days in decreasing doses, commencing with a dose of 16 mg/day. TSH, FT4 and hTRAb serum concentrations were measured prior to, and 14, 30, 60 days and 12 months after administration of 131I, always accompanied by an ophthalmic evaluation. RESULTS: In the studied group, mean TSH and FT4 concentrations prior to treatment were 0.05 +/- 0.08 microU/ml and 23.7 +/- 10.7 pmol/l, respectively. Mean 131I activity applied in this group was 605.0 +/- 89.0 MBq. No significant differences were stated between values of respective parameters in the studied and control groups. Prior to treatment, median hTRAb concentrations in the studied and control groups were 6.8 U/l (max 53.8, min 0.1) and 8.9 U/l (max 57.1, min 4.2), respectively, and did not differ significantly. After 14 days post commencing MP treatment the median hTRAb concentration in the studied group decreased (4.5 U/l, max 51.1, min 0.1) with respect to the control group (7.5 U/l, max 50.0, min 2.9). After 60 days and 12 months, median hTRAb concentrations in the studied group were 8.3 U/l (max 16.9, min 0.7) and 8.5 U/l (max 9.8, min 3.0) respectively, being higher than those in the control group and also higher than the initial value in studied group. Cured were 16/21 patients in the studied group and 16/18 patients in the control group. Within 12 months observation, progression of GO symptoms in 2 patients (9%) of the studied group was noted and exophthalmos observed in 3 patients (17%) of the control group. CONCLUSIONS: In patients with mild GO treated with methyloprednisolone 131I administration is effective and does not lead to aggravation of GO symptoms, compared with the control group. Long-term elevation of hTRAb concentration in studied and control group of patients with Graves' disease treated with 131I1 was found.