Use of aspirin or other anticoagulants in addition to radiation therapy or surgery may reduce the risk of dying of prostate cancer by more than half, according to a large study presented at the 52nd Annual Meeting of the American Society for Radiation Oncology.
“Evidence has shown that anticoagulants may interfere with cancer growth and spread,” said lead author Kevin Choe, MD, PhD, of the University of Texas Southwestern Medical School in Dallas. “If the major effect of anticoagulants is preventing metastasis…this may be why previous clinical trials with anticoagulation medications produced mixed results, since most patients in these trials already had metastasis,” he explained. “If the cancer has already metastasized, then anticoagulants may not be as beneficial.”
The study included 5275 men with localized adenocarcinoma of the prostate who were treated with radical prostatectomy or radiotherapy. Of these patients, 1982 were taking anticoagulants (428 warfarin, 287 clopidogrel, 26 enoxaparin, 1649 aspirin, 408 a combination of anticoagulants) at enrollment or during follow up. Patients were classified as having high-, intermediate- or low-risk disease according to National Comprehensive Cancer Network criteria.
Among men who used anticoagulants after either surgery or radiation, the risk of prostate cancer–specific mortality was 4% at 10 years compared with 10% in men who did not use anticoagulants. The risk of developing bone metastasis was also reduced in these men. The benefit was most prominent with aspirin, and men with high-risk prostate cancer, for whom treatment options are limited, showed the greatest reduction in risk.
Despite the favorable findings, the authors say that further studies are needed before addition of aspirin to prostate cancer therapy can be recommended as standard practice.