Aspirin may prevent prostate cancer recurrence

The use of anticoagulant drugs such as aspirin appears to reduce the likelihood that cancer will recur in men undergoing radiation treatment for prostate cancer, researchers report.

"We have found that taking an anticoagulant reduces the risk [of recurrence] by almost half," said Kevin S. Choe, MD, PhD, a radiation oncologist at the University of Chicago.

Anticoagulant drugs, or anticoagulants were studied Coumadin, Plavix and aspirin.

"Prostate cancer is very common among older men, the same people who have cardiovascular risk factors and often require blood thinners to prevent a heart attack," he tells WebMD Choe. "So I wanted to see if there was an interaction between the two."

Animal research and laboratory suggests that anticoagulant drugs may interfere with tumor growth and spread of cancer, Choe says.

Furthermore, research suggests that drugs can cause molecular changes that make cancer cells more sensitive to radiation, says Alan, University of Miami, Pollack, MD, PhD, who was not involved with the work.

The findings were presented at the annual meeting of the American Society of Radiation Oncology.
Anticoagulant medications reduce the risk of prostate cancer recurrence

The study included 662 men with prostate cancer undergoing radiation treatment at the University of Chicago from 1988 to 2005.

Of the total, 196 were taking aspirin, 58 were taking Coumadin, and 24 were in Plavix. The other men were not taking any anticoagulant medication.

Some four years after they are treated, cancer recurrence in only 9% of men taking an anticoagulant drug, compared with 22% of those who were not taking medications.

After taking into account other risk factors for recurrence, taking an anticoagulant medication was associated with a 46% lower risk of recurrence, Choe says.

The benefit was more pronounced in men at high risk for aggressive cancer that had not yet spread (metastasis) at the time of radiation treatment. In this group, cancer was repeated in 18% of men treated with anticoagulants compared to 42% of men do not take drugs.

Cancer recurrence was defined as an increase in levels of prostate specific antigen, or PSA. After radiation therapy, PSA level usually drops to a low stable level. Increased PSA levels are usually a sign of recurrence, Choe says.

Benefited anticoagulant drugs and men, regardless of whether they received traditional external beam radiation therapy or radioactive seeds. The study included men who received new forms of radiation therapy such as proton therapy.

The researchers analyzed the three drugs separately.

Choe notes that men with prostate cancer should not start taking anticoagulant drugs for cancer control purposes.

The drugs have risks of their own, including internal bleeding, he says. Choe previous investigation showed that Plavix Coumadin and increase the risk of rectal bleeding in men undergoing radiation treatment.

"We need more data from a larger study before we can say with confidence that the benefits outweigh the risk of toxicity," he says.

But if your doctor has prescribed the drug for health reasons of the heart, "this may be an added benefit," says Choe.