A new study published in the Journal of Clinical Oncology found that aspirin was associated with a reduced risk of prostate cancer–specific mortality in patients previously treated with prostatectomy or radiotherapy. The reduction of prostate cancer deaths was seen especially in men with high-risk disease (4% vs 19% at 10 years; P < .01).
Previous studies have shown that aspirin can help prevent colorectal cancers. This study, however, focused on patients who were already diagnosed with and treated for prostate cancer. Most patients in the anticoagulant group (84%) received aspirin. "In this cohort of patients with cancer already established, it was associated with a reduction in prostate cancer mortality," said Stanley L. Liauw, MD, one of the authors of the study, in an email to Cancer Network. Dr. Liauw is an associate professor of radiation and cellular oncology at the University of Chicago Medicine, specializing in genitourinary and gastrointestinal cancers.
The study was designed to analyze the risk of prostate cancer–specific mortality (the primary endpoint) in patients receiving anticoagulants—clopidogrel, enoxaparin, warfarin, and/or aspirin—compared to those who did not take anticoagulants. Analysis by type of anticoagulant suggested that the reduced risk of prostate cancer death was primarily seen in those patients taking aspirin. Recurrence of disease and distant metastasis were also studied.
Patients included in the study were from the Cancer of the Prostate Strategic Urologic Research Endeavor database.
Included in the analysis were 5,955 prostate cancer patients with localized disease treated with radical prostatectomy or radiotherapy. Of those, 2,175 patients (37%) received anticoagulants and had a reduced risk of prostate cancer–specific mortality (3% vs 8% at 10 years; P < .01). The benefit for patients taking aspirin was observed across both treatment modalities (surgery or radiation).
A lower risk of disease recurrence was seen in the anticoagulant group (28% vs 36% at 10 years) as was a lower risk of bone metastasis (3% vs 6% at 10 years).
Doses were not available to the authors. "The optimal usage of aspirin, as well as the potential toxicity, should be addressed in a prospective study," wrote the authors. The authors conclude that "a randomized comparison would be valuable to corroborate this association and justify a routine recommendation of aspirin in patients with prostate cancer."
Aspirin, a nonsteroidal anti-inflammatory drug, has been linked to a reduction in the risk of colorectal cancer, but how the over-the-counter drug works in this context "is anyone’s best guess," said Dr. Liauw. "It’s role in the primary prevention of new cancers does suggest some inhibitory effect on carcinogenesis and anti-inflammatory effects are certainly a possibility."
"Alternatively," said Dr. Liauw, "it could also be related to inhibition of metastasis/invasion as related to its antiplatelet effects, or some other mechanism."