High Rates of Underlying Thyroid Cancer in Patients Undergoing Thyroidectomy for Hyperthyroidism

The rate of thyroid cancer in patients with hyperthyroidism is reported to be rare, and patients with toxic thyroid nodules do not routinely undergo fine-needle aspiration (FNA) to evaluate for malignancy. However, higher rates of malignancy in hyperthyroid patients may exist than previously reported. This study examines the rate of malignancy in patients with hyperthyroidism who have undergone thyroidectomy.

A retrospective review of prospectively collected data of 138 patients with hyperthyroidism who underwent thyroidectomy at a single institution was performed. Patients were divided into three groups: Graves' disease (n = 80), toxic multinodular goiter (n = 46), and toxic solitary nodule (n = 12). Patients with previous thyroid surgery were excluded from the study. All patients had biochemical confirmation of hyperthyroidism with thyroid-stimulating hormone <0.1 mIU/L and clinical diagnosis by a referring physician.

Of 138 patients, 22% (31/138) were found to have malignancy on final pathology. The breakdown of malignancy by hyperthyroid condition was as follows: 16% in Graves' disease, 24% in toxic multinodular goiter patients, and 50% in toxic solitary nodule patients.

There is a clinically significant rate of malignancy seen in patients who undergo thyroidectomy for hyperthyroidism. Patients with distinct thyroid nodules in the presence of hyperthyroidism may have the highest rates of malignancy and should undergo appropriate workup with ultrasound and FNA to exclude underlying malignancy. In cases with suspicious ultrasound features and/or FNA cytopathology, surgical treatment should be considered as initial management.