Aspirin can interfere with prostate cancer therapy, study warns

Taking low-dose aspirin can cut short hormone therapy used to treat prostate cancer and lead to a lower chance of survival, Boston doctors warn.

In a letter appearing in tomorrow’s New England Journal of Medicine, authors Dr. Anthony V. D’Amico and Dr. Philip W. Kantoff of the Dana-Farber Cancer Institute and Ming-Hui Chen of the University of Connecticut report that the use of low-dose aspirin can cause abnormal liver function tests in men receiving hormones for prostate cancer. That meant an early end to part of their hormone therapy and more than triple the risk of death compared to men who completed full hormone therapy, the researchers' analysis showed.

"It is important for the public to be aware that commonly used medications can interfere with the delivery of full-dose cancer therapy that may compromise curability,” D'Amico said in a statement about the findings. “Therefore, patients should inform their doctors about all of the medications (including non-prescription over-the-counter drugs such as baby aspirin) that they are taking."

The researchers studied the records of 206 men with high- or intermediate-risk localized prostate cancer who were enrolled in a randomized clinical trial comparing radiation plus hormone therapy to radiation alone. D’Amico and his co-authors wanted to see if commonly used drugs such as low-dose aspirin or the cholesterol-lowering drug Lipitor were associated with halting hormone therapy after abnormal liver function was found.

The anti-androgen drug flutamide, one of the two kinds of hormones administered in the study, was stopped early in 37 percent of aspirin users because of tests that showed liver-function abnormalities. The hormone was discontinued in 16 percent of men not taking aspirin who also had abnormal liver-function tests. The Lipitor was not linked to liver problems.

After more than seven years of follow-up, the risk of death was 3.5 times as high among men who completed the full six months of only one kind of hormone therapy as it was among men who received the full course of both kinds of hormones. Men who received radiation alone had a death rate 6.1 times as high as those who got six months of both hormones.