The extent of thyroidectomy in Graves' disease is still controversial. In our institution, long term euthyroidism without thyroxine replacement therapy has been aimed and, thus, subtotal thyroidectomy has been employed. We prospectively studied whether the surgical outcome was improved by a strategy of leaving smaller thyroid remnants. Between 1989 and 1998, 1897 patients with Graves' disease were treated by subtotal thyroidectomy and their thyroid function could be determined 2 to 3 years after thyroidectomy. The 10-year period was divided into 3 parts, '89-'91 (Period 1, n = 690), '92-'94 (Period 2, n = 587) and '95-'98 (Period 3, n = 620). Different maximum thyroid remnant sizes were prospectively established for each period: up to 7 g left in Period 1, up to 6 g in Period 2 and up to 5 g in Period 3. Thyroid function 2 to 3 years after thyroidectomy and the occurrence of surgical complications were compared among the three groups. The relapse rate for Period 1, Period 2, and Period 3 was 14.1%, 12.6%, and 10.9%, respectively, and the rate of euthyroidism decreased and rate of hypothyroidism increased from period to period. Surgical complications increased in Periods 2 and 3. For preventing relapse, the strategy of reducing the thyroid remnant is effective. Subtotal thyroidectomy leaving 3-4 g remnant tissue is a suitable surgical option for Graves' disease.
The Japan Endocrine Society