Evaluation of Thrombotic Risk in Thyroid Cancer

Abstract

Introduction: Current guidelines from the International Society of Thrombosis and Hemostasis recommend limited screenings for deep vein thrombosis (DVT) or pulmonary embolism (PE) with no identifiable precipitating factor (termed unprovoked). There is paucity of data with regards to thyroid cancer screening in the setting of an unprovoked VTE. Studies from Europe have shown an association between VTE and thyroid cancer; however, these studies do not account for differences in iodine availability, thus the need for studies in the United States. Understanding the risk of thyroid cancer as a provocative factor in developing a deep venous thrombosis (DVT) or pulmonary embolism (PE) may be able to facilitate case detection of disease and prevent future morbidity and mortality from thyroid cancer and/or VTE. Objectives: The primary objective of this study is to understand the risk of developing VTE in the setting of thyroid cancer. Methods: In this retrospective chart review study, we reviewed electronic medical records of patients with a history of DVT or PE between ages 18-99, presenting to all outpatient clinics at a single academic medical center in New Jersey between October 1, 2015, and Dec 31, 2018. We screened for coexistent cancer history among this group, and from this sample we further isolated cases of thyroid cancer. Results: 345 patients were found to have a history of VTE. 187 were female (54%) and 113 (29%) had a history of malignancy. The most common cancers were breast (19%), colorectal (9%), leukemia (9%), prostate (8%), and lymphoma (8%). Thyroid cancer accounted for 2% of all discovered cases. Conclusion: In this retrospective analysis, 2% of all patients with VTE and cancer carried a diagnosis of thyroid cancer. Although this suggests a relatively low risk, given the medical burden of a venous thromboembolism and the comparable proportion of thyroid cancer in all new cancer cases, thyroid cancer should be considered a provoking factor in unprovoked VTE.