Incidental but Not Insignificant: Thyroid Cancer in Patients with Graves Disease

Graves disease is the most common cause of hyperthyroidism in the US. Treatment with antithyroid drugs and radioactive iodine is more commonly used than surgical management with total thyroidectomy (TTx). However, incidentally discovered thyroid cancer (TC) has been described on surgical pathology from patients who underwent surgical treatment of Graves disease, which would be missed with these other treatment strategies. We sought to determine the incidence rate of TC among patients with surgically treated Graves disease.We retrospectively reviewed patients with Graves disease who underwent TTx at a single institution from 2011 to 2023. Pathology reports were reviewed for TC. Patient demographics, preoperative laboratory and radiological evaluations, preoperative medical management, and surgical outcomes were compared between patients with and without incidental TC.There were 934 patients, of whom 60 (6.4%) patients had incidentally discovered TC on pathology. The majority (58.3%) of patients had papillary thyroid carcinoma, followed by 33.3% with papillary microcarcinoma. Preoperative ultrasound (US) was obtained in 564 (60.4%) of patients, with 44.3% with nodules, but only 34 (13.7%) of those with nodules had TC on final pathology. Preoperative fine needle aspiration was obtained in 15 patients with TC, and 8 patients (53.3%) were reported as benign lesions, which ultimately had TC on final pathology. There was no difference in sex, race or ethnicity, preoperative medical management, and postoperative outcomes between the 2 groups.Incidental TC was found on surgical pathology in 6.4% of patients undergoing TTx for Graves disease. Preoperative imaging with US and fine needle aspiration were often unreliable at predicting TC. The incidence of TC should not be underestimated when counseling patients on definitive management for Graves disease.