[The prevention of the recurrence of endemic goiter. The efficacy of a once-a-week dose of 1.53 mg iodide].

Objective: To investigate the efficacy of 1.53 mg iodide administered once weekly in the prophylaxis of goitre recurrence in patients with endemic euthyroid goitre after initial treatment to reduce the goitre size.
Patients and Methods: 46 consecutive patients who had undergone initial L-thyroxine, iodide or combined treatment were included in the prospective study. Thyroid volume was measured sonographically at the beginning as well as 6 and 18 months later. An increase in thyroid volume of more than 15% was taken as recurrence.
Results: The study was concluded in 41 patients. During the prophylaxis mean thyroid volume increased from initially 21.7 +/- 9.9 ml to 22 +/- 10.9 ml after 6 months and to 24.5 +/- 12.1 ml after 18 months (P < 0.01). While thyroid volume remained unchanged in at least two thirds of patients, a recurrence occurred in 32% (n = 13; from initially 22.7 +/- 9.7 ml, to 26.3 +/- 11.3 ml at 6 months and to 29.7 +/- 12.3 ml at 18 months). In all patients with a recurrence a doubling of the iodide dosage to twice weekly 1.53 mg for 6 months reduced thyroid volume again (mean of 25.7 +/- 10.0 ml; P < 0.01).
Conclusions: In at least two third of patients a once-weekly dose of 1.53 mg iodide is a reliable means of preventing a recurrence of endemic euthyroid goitre, but in the remainder the same dose must be increased to twice weekly.