[Treatment with (131)I of toxic multinodular goiter. Assessment of a fixed dose protocol].

Objective: Present the results of treatment with 131I in a cohort of 119 patients diagnosed of toxic multinodular goiter (TMG) from a specific geographic area who had been treated with fixed doses of isotopes (555 MBq). The indication for the administration of the 131I was hyperthyroidism correction in all of the cases.

Material and Methods: 111 of the 119 patients treated were women (93%) and 8 were men (7%) and their ages ranged from 38 to 88 years. The follow-up periods were always greater than one year (1.78 +/- 1.05 years). Treatment with thyroid medication was discontinued in all of the patients at least 7 days prior to the administration of the isotope.

Results: 93 (78.1%) of the 119 patients remained euthyroidic, 10 (8.4%) presented hypothyroidism, 11 (9.2%) hyperthyroidism and 5 (4.2%) had sub-clinical levels of hyperthyroidism at the end of the follow-up period. No statistically significant relationship were found between hypothyroidism, gender and previous administration of thyroid medication.

Conclusions: The use of 131I is an alternative to the treatment of TMG produced hyperthyroidism. The fixed doses of 555 Mbq that we propose are comfortable, make it unnecessary for the patients to travel in extensive geographic areas and produce a low rate of hypothyroidism. In our opinion, the differences in the iodine content of the diets that continue to exist are one of the factors that could influence in the differences in results observed in the different series, although other factors, such as the size of the goiter and the heterogeneity of the radioisotope uptake can contribute to the variations found in our patients.