Efficacy evaluation of radioiodine on remaining tissue after surgery for thyroid carcinomas

Iodine-131 is an effective treatment for patients with papillary or follicular carcinoma of the thyroid. After total or subtotal thyroidectomy, all the remaining tissue should be totally destroyed by radioiodine. Three to four months later, a scintigraphic control is performed using a lower activity of iodine-131, with high TSH serum levels. The treatment efficiency is assured by a complete absence of the cervical radioiodine uptake. Our purpose was to evaluate the efficacy of this treatment by studying 175 histories between 1987 and 1992. The parameters we studied are histology, node invasion, age, sex, TSH and thyroglobulin serum levels, delivered dose to the residual tissue (after previsional dosimetry) and ingested radioiodine activity. In 84% of cases, there was no residual fixation of radioiodine after three to four months. The best prognosis concerned women with high TSH and low TG levels, and no node invasion. Other parameters, age, histology previsional dosimetry and ingested activity were not predictive. (authors). 9 refs., 1 tab