Prostate Cancer Patients on Aspirin Therapy More Likely to Die, Study SaysDec 31, 2007 | Parker Waichman LLP Prostate Cancer, hormone treatments and aspirin therapy could be a deadly combination. According to research published in the December 27th issue of the New England Journal of Medicine, men undergoing hormone therapy for prostate cancer—and who take baby aspirin to protect their heart—run a significantly higher risk of dying. Apparently, baby aspirin side effects interact with the hormone therapy, elevating liver-function test levels. Liver function testing is a routine part of cancer-fighting treatments. Because of this, the man must stop potentially lifesaving hormone therapy. Hormonal therapy involves reducing levels of male hormones called androgens and is a common treatment for prostate cancer. Because this type of therapy can raise the risk of a heart attack, men who are older or have known coronary risk factors such as diabetes or smoking, generally include baby aspirin in their treatment protocol while undergoing hormone therapy because aspirin helps prevent blood clots.
"Aspirin is being prescribed more widely for these men so we looked to see if there was any effect of aspirin on prostate cancer outcomes," said lead researcher Dr. Anthony V. D'Amico, chief of the division of genitourinary radiation oncology at Brigham & Women's Hospital and the Dana-Farber Cancer Institute, both in Boston. The authors analyzed data on 206 men with localized prostate cancers who were enrolled in a trial to compare radiation therapy alone with radiation therapy plus hormone therapy. The hormone therapy included six months of the anti-androgen flutamide, which had a tendency to elevate liver-function test results. Although elevations were benign, they meant stopping hormonal therapy, at least temporarily, D'Amico explained. Men who didn't complete six months of hormone therapy were 3.5 times more likely to die compared to men receiving the full course of therapy. "It was sort of a paradoxical finding," D'Amico said. "Men who were taking aspirin were more likely to die of prostate cancer than those who were not, which didn't make sense at first."
Researchers realized the men taking aspirin were more likely to have to stop hormone therapy. Because liver function is monitored when undergoing hormone therapy, "When the tests elevate, you take the patient off of hormone therapy till the tests normalize, then you restart the therapy," said D’Amico. For example, for test animals taking aspirin while undergoing hormone therapy, aspirin magnifies 100-fold in terms of how much gets into the blood, resulting in a toxic dose of aspirin, D’Amico explained. Although this type of study can't establish a cause-and-effect association, it does appear likely, D'Amico said. "If a man is taking baby aspirin just to prevent heart disease, we would ask the oncologist to ask the primary-care physician if he could come off the baby aspirin for the months while he's getting cancer therapy. If the aspirin is just for prevention, this is probably the simplest thing to do," he said. "But if the patient is on aspirin because he absolutely needs it, then they'd have to treat the prostate cancer without hormone therapy. It really comes down to a trade-off: How much do they need the aspirin versus how much do they need hormonal therapy, and there are alternative treatments for prostate cancer."