Coexistence of hyperthyroidism and thyroid cancer.

Abstract

AbstractAmong 702 patients who underwent surgery for hyperthyroidism, thyroid cancer was demonstrated histologically in 18 patients (2.6%). A higher incidence of cancer occurred in patients with multinodular toxic goiter (3.3% of 317 patients) and uninodular toxic goiter (2.9% of 207 patients), whereas only 1.1% of 178 patients operated for Graves' disease had coexistent thyroid cancer. In addition, 5 patients who underwent surgery for thyroid cancer were found preoperatively to be hyperthyroid, increasing the total number of patients with coexistent thyroid cancer and hyperthyroidism to 23. Among 554 patients with thyroid cancer operated upon during the same period, 4.2% were hyperthyroid (8.6% of patients with papillary thyroid carcinoma, 4.5% with follicular thyroid carcinoma, and only 0.5% with undifferentiated thyroid carcinoma).Thyroid cancer was identified within a toxic nodule in 6 patients, in surrounding tissue suppressed by solitary toxic nodules in 4 patients, in cold nodules coexisting with multinodular toxic goiters in 8 patients, and microscopically disseminated in diffuse toxic goiters in 2 patients; 3 patients presented large inoperable and metastatic tumor masses. Although in 8 of the 23 patients (35%) the thyroid cancer was advanced (extrathyroid growth of the primary tumor and/or regional metastases and/or distant metastases), cancer was diagnosed preoperatively in only 5 patients (22%).This study demonstrates that hyperthyroidism does not prevent thyroid cancer and that patients with nodular toxic goiters in particular must be carefully evaluated with regard to risk factors, history, and clinically suspicious signs. Needle biopsy should not be restricted to cold nodules. Surgery rather than radioactive iodine or antithyroid therapy is the treatment of choice in toxic nodular goiter.