Potential Cardiovascular Risks of Thyroid Cancer Therapy and Hyperthyroidism
Posted: Wednesday, January 20, 2021
Few thyroid cancer studies have shown a clinical significance between thyroid-stimulating hormone (TSH) suppression therapy and cardiovascular risk. Joop D. Lefrandt, MD, PhD, of the University Medical Center Groningen, Netherlands, and colleagues published their research about the influence of TSH suppression therapy and certain preexisting conditions—such as clinical and subclinical hyperthyroidism—on cardiovascular risks in Endocrine Connections (the official journal of the Society for Endocrinology and the European Society of Endocrinology).
The investigators assessed the potential association between TSH suppressive therapy for differentiated thyroid cancer and an increased risk of cardiovascular events in more than 500 patients from 10 published studies since 2010 compared with 1,500 age- and sex-matched controls. A 2.5-fold increase in atrial fibrillation and a 3.3-fold increase in cardiovascular mortality were identified; both were considered to be independent of other well-known risk factors. Although the authors noted that an obvious relation with TSH suppression in these patients was lacking, “other data have shown a relationship between the risk of cardiovascular mortality and TSH level.”
The investigators also explored “a probable tendency toward thrombosis” in patients with hyperthyroidism, suggesting they may be at increased risk for atrial fibrillation, heart failure, and cardiovascular risk. The investigators used a high-risk vascular fingerprint (at least three risk factors) before the start of chemotherapy to identify patients at the highest risk of arterial cardiovascular events. The cutoff values included a body mass index of more than 25 kg/m2, current smoking, blood pressure higher than 140/90 mm Hg, dyslipidemia, and use of blood glucose–lowering agents. “Although not externally validated, these factors promised to be useful for selection of patients who might benefit from preventive strategies,” the authors proposed.
This tool was applied to 619 patients with differentiated thyroid carcinoma who were diagnosed between 1980 and 2010. After initial diagnosis, 60 developed a cardiovascular event within a median follow-up of 12.6 years, with 39 in the high-risk category. Of the 426 patients determined to be at low risk, 21 experienced a cardiovascular event, whereas 39 at high risk developed a cardiovascular event.
Disclosure: The study authors reported no conflicts of interest.