The value of L-thyroxine in the supressive therapy of euthyroid nodules and in the prevention of post-thyroidectomy recurrences.

Long-term L-thyroxine (L-T4) suppression therapy was applied to 133 patients with euthyroid nodular goiter (126 females/7 males) and to 148 patients (136 females/12 males) with post-thyroidectomy recurrence between the years 1980 and 1986. The results are interpreted as "Complete Success" if the nodule disappeared, "Partial Success" if it became smaller, "Late Unresponsiveness" if the nodule first decreased then increased in volume and "Unresponsiveness" when it did not change. In the group of euthyroid nodules, complete success was obtained with 150-200 micrograms/L-T4 daily administration. But in the recurrence group the response to the same dose was lower than in the first group and most of them were partial responders. On the other hand, we found highly significant differences in the incidence of postoperative recurrences, between the group of patients subjected to a long term L-T4 suppression therapy with the recurrence and prophylactic therapy with L-T4. While postoperative recurrence was only 6.35% in the long term L-T4 receiving group, it was very high (80.95%) in the non-treated group. Furthermore, in the group of patients taking L-T4 suppression therapy only for a short period, the incidence of recurrence was 12.70%. As a result of this study, we concluded that routine long term L-T4 suppression therapy is necessary both for the treatment of selected euthyroid nodules without any suspicion of malignancy for the prevention of post-thyroidectomy recurrences.