Androgen-Deprivation Therapy May Increase Risk for QT Prolongation and Torsades de Pointes
In a study published by Salem et al in Circulation, researchers examined how several testosterone-blocking drugs commonly used in the treatment of prostate cancer affect the heart's QT interval.
The longer a QT interval—typically measured by an electrocardiogram—the more at risk a person is to develop serious heart rhythm problems and a condition called torsade de pointes, which can result in sudden death. Women naturally have a longer QT interval than men, and they are at higher risk for this form of arrhythmia.
“Testosterone is in part responsible for the protective effect in men,” said lead study author Joe-Elie Salem, MD, PhD, Associate Professor of Cardiology and Pharmacology at Sorbonne University in Paris. “We wanted to see if blocking testosterone with antiandrogens could lead to acute QT prolongation and sudden death.”
Methods
Dr. Salem and colleagues used VigiBase, a global health database of reports of suspected adverse effects of medicines filed since 1968. They searched for cases of men with long QT, torsade de pointes, or a sudden death associated with testosterone-blocking therapy.
Seven of the 10 drugs reviewed were disproportionally associated with either long QT, torsade de pointes, or sudden death. Enzalutamide was linked with more deaths than any other antiandrogen.
Dr. Salem said more research should explore the interaction between antiandrogens and other drugs and conditions that also can also prolong QT. For example, electrolyte disorders caused by low potassium levels can impact the heart's rhythm.
“When you're giving antiandrogen drugs, you should probably monitor for torsade de pointes and be very careful about controlling the other risk factors for QT prolongation,” he explained.
Disclosure: For full disclosures of the study authors, visit ahajournals.org.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
