The efficacy of long term thyrostatic treatment in elderly patients with toxic nodular goitre compared to radioiodine therapy with different doses

The objective of the study was to investigate the efficacy of long term thy rostatic versus radioiodine treatment of hyperthyroidism in old age. Our st udy is a retrospective analysis of the therapeutical outcome in 66 patients over 60 years of age with toxic nodular goitre. The patients were divided in two groups: Group A: 28 patients on methimazole treatment: starting dose 5-30, median (M) 10 mg, maintenance dose 2.5-15 (M = 5) mg, follow up 6 to 240 months (M = 23.5 months). Group B: 38 patients treated by either 100-3 00 MBq (N = 14, subgroup B1) or 325-1000 MBq (N = 24, subgroup B2) I-131, f ollow up: 18 to 156 months (M = 48 months). The efficacy of the different t herapeutical approaches were compared by calculating the occurrence rate of persisting and relapsing thyroid dysfunctions and associated side effects. The 28 patients on methimazole treatment became euthyroid after 1-16 (M = 5) months bur numerous relapses occurred in the follow up: hyperthyroidism, clinical: 5, subclinical 13, (relapse duration: M = 8 months; associated s ymptoms: hypertension in 4, cardiac arrhythmia in 3, cerebral embolism in 1 , angina pectoris in 2, weight loss in 2 cases). Poor patient's compliance (9/28) or dose reduction by the physician (5/28) were the main causes of th e relapses. Transient clinical(3 cases) or subclinical (6 cases) hypothyroi dism also occurred (duration: 1-3 M = 2 months, no clinical symptoms). In 7 out of 14 (50%) patients receiving 100-300 MBq I-131 (Group B1) hyperthyro idism persisted (versus 4/24-16.7%-in Group B2 following 325-1000 MBq I-131 : chi((1))(2) = 4.78 P = 0.028), methimazole treatment had to be continued in 9/14 patients (64.3%) (versus 5/24-20.8%- in Group B2.. chi((1))(2) = 7. 18 P = 0.0074) and in 5/14 (35.7%) the radiotherapy had to be repeated (ver sus 5/24-20.8%-in Group B2, not sign.). Our conclusions are: 1) long term t hyrostatic treatment is not safe in elderly patients with toxic nodular hyp erthyroidism, mainly because of poor compliance or dose reduction by the ph ysician; 2) radioiodine treatment as the first choice should be recommended for these patients and higher doses should be preferred.