Long-term observation of thyroid function after surgical treatment of thyrotoxicosis.

During the 10-year period from 1960 to 1970 a total of 213 patients with diffuse or nodular toxic goitre underwent subtotal thyroidectomy. A short-term preoperative treatment with antithyroid drugs and iodine was given systematically. The observation period ranged from 5 to 15 years, average 9 years. A total of 203 patients (95%) were traced and followed up. The concentration of se-T4, se-T3, and se-TSH was measured and in selected cases a TRH test and BMR was carried out in addition. All thyroid specimens were re-examined by the same pathologist for histological grading. It was found that 85% of the patients had been rendered euthyroid for 5 years or more. The recorded incidence of thyroid hypofunction was 6% and the incidence of recurrent thyrotoxicosis was 9% of the series. Se-TSH was found to be elevated in 17%. The correlation between elevated se-TSH and se-T4 values was calculated and found to be fairly reasonable (r = -0.66). It is concluded that subtotal thyroidectomy preceded by short-term antithyroid drug therapy supplemented ultimately with iodine offers significant advantages in the management of thyrotoxicosis by rendering 85% of patients euthyroid on long-term surveillance.