Toulis KA, et al. - For many years, prevention of differentiated thyroid cancer (DTC) recurrence has been achieved with exogenous TSH suppression though it may be associated with increased circulatory disease risks, so researchers analyzed the risk of circulatory disease in patients without a history of cardiovascular disease treated for DTC. For this analysis, 3,009 patients who were treated for DTC without pre-existing cardiovascular disease were recognized and matched to 11,303 controls; they were then followed for a median of 5 years. During the observation period, 1,259 incident circulatory events were recorded. In patients with DTC, the risk of atrial fibrillation and stroke was significantly higher. Overall, the investigators suggested periodic screening for this arrhythmia due to the increased risk of AF in patients treated for DTC. The increased risk of stroke and TIA warrants further investigation, even without evidence of increased ischemic heart disease or heart failure risk.