[Thyroid cancer in patients with hyperthyroidism]

The prevalence of thyroid carcinoma in hyperthyroidism remains controversial. The aim of this retrospective study was to evaluate prevalence.

The prevalence of thyroid carcinoma was studied in 861 patients operated for clinical or infraclinical hyperthyroidism between 1992 and 1999. One hundred and fifty patients had a hot nodule, 13 of them with an associated goiter. Four hundred five patients had Graves' disease and 306 had a multinodular goiter. Multiple sections were made in all surgical specimens for pathology study.

Prevalence in solitary nodules was 1.45%. For Graves' disease patients, it was 4.1%. Prevalence among patients with multinodular goiter was 4.9%. Among the cancers, 83% were microcarcinoma. Parathyroid morbidity after subtotal and total thyroidectomy was 0.56% and recurrent hyperthyroidism occurred in 1.6%.

These findings are grossly identical to those observed in simple, nontoxic diffuse multinodular goiter. It would therefore be difficult to incriminate hyperthyroidism as playing a causal role in the development of thyroid cancer. These results do however provide an argument favoring total or near total thyroidectomy when surgery is performed in patients with hyperthyroidism.