Do prostate cancer drugs interact with certain anticoagulants to increase bleeding and clotting risks?

In a study of adults with advanced prostate cancer taking androgen-receptor pathway inhibitors and different types of anticoagulants, investigators found no evidence of an increase in patients’ bleeding or clotting risks, despite previous lab results that raised alarms. The findings are published by Wiley online in CANCER, a peer-reviewed journal of the American Cancer Society.

Thromboembolism, caused by a circulating blood clot that gets stuck and causes an obstruction, is the second leading cause of death in people with cancer, surpassed only by progression of the cancer itself. Anticoagulants (blood thinners) are standard therapy to treat or prevent thromboembolism. For individuals with advanced prostate cancer, thromboembolism can be especially worrisome because lab experiments have indicated that androgen-receptor pathway inhibitors, which are recommended for nearly all patients with advanced prostate cancer, can interact with certain anticoagulants-specifically, direct oral anticoagulants (DOACs).

To investigate whether these lab-based findings correlate to real concerns in patients, researchers evaluated outcomes in patients taking both anticoagulants and androgen-receptor pathway inhibitors, including enzalutamide, apalutamide, and abiraterone.

In the retrospective population-based analysis of 2,997 Canadian adults with prostate cancer who were prescribed anticoagulants (DOACs or non-DOACs) and enzalutamide or apalutamide between 2012 and 2023, investigators found no increased risks of clotting in the DOAC versus non-DOAC groups. Similarly, investigators compared DOAC and non-DOAC groups combined with abiraterone and did not find an increased risk of bleeding.

“As clinicians, we are faced with the question of choosing the best anticoagulant option for patients on a daily basis, and the complexity further increases in patients with cancer taking many other medications including anticancer therapies that could cause concerning drug–drug interactions,” said lead author Tzu-Fei Wang, MD, of the University of Ottawa at The Ottawa Hospital and the Ottawa Hospital Research Institute. “Our findings suggest that pharmacokinetic drug–drug interaction concerns may not translate into adverse clinical outcomes in the real world. These results can help clinicians and patients feel more confident when managing anticoagulation alongside modern prostate cancer treatments.”

Reference:

Tzu-Fei Wang, Anna Clarke, Mitchell Rath, Samantha Yoo, Deena Fremont, Cynthia Wu, Risks of thrombosis and hemorrhage in concurrent use of anticoagulants and potential interacting prostate cancer agents, Cancer, https://doi.org/10.1002/cncr.70266.