Is there a clinically significant increased risk of venous thromboembolism with the use of fulvestrant for metastatic HR+ breast cancer?

In a patient with a history of VTE (now off anticoagulants), is it safe to administer fulvestrant?

1 Answer

Mednet Member

Medical Oncology · Icahn School of Medicine at Mount Sinai

Answered on

The reason for VTE? Post-operative, trauma, hypercoagulability due to having cancer or its treatment, hereditary hypercoagulability, or idiopathic? I am going to assume that the VTE was self-limited and treated with a course of anticoagulation. Does fulvestrant cause VTE? Ideally, a randomized placebo-controlled trial of fulvestrant is needed to answer this question. No such trial exists that I am aware of. Wang et al in 2018 (PMID 29974356) published a meta analysis of 7 randomized trials of fulvestrant versus aromatase inhibitors in over three thousand with advanced breast cancer. There were no reports of VTE. In the FDA package insert, there is no mention of VTE. CDK 4/6 inhibitors in real world experience have a small increase in risk of VTE (West et al., PMID 33527479).