Aspirin May Prevent Prostate Cancer Recurrence
Anti-clotting Medications Lower Odds of Recurrence
Nov. 6, 2009 (Chicago) -- The use of anti-clotting drugs, including aspirin, appears to lower the odds that cancer will recur in men undergoing radiation treatment for prostate cancer, researchers report.
"We found that taking an anticoagulant lowers the risk [of recurrence] by almost half," says Kevin S. Choe, MD, PhD, a radiation oncologist at the University of Chicago.
The anti-clotting medications, or anticoagulants, studied were Coumadin, Plavix, and aspirin.
"Prostate cancer is very common among older men, the same people who have cardiovascular risk factors and often require anticoagulants to prevent a heart attack," Choe tells WebMD. "So we wanted to see if there was an interaction between the two."
Research in animals and in the lab suggests that anti-clotting medications can interfere with tumor growth and cancer spread, Choe says.
Also, research suggests that the drugs may cause molecular changes that make cancer cells more sensitive to radiation, says the University of Miami's Alan Pollack, MD, PhD, who was not involved with the work.
The findings were presented at the annual meeting of the American Society for Radiation Oncology.
Anti-clotting Medications Cut Risk of Prostate Cancer Recurrence
The study involved 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 on Plavix. The other men weren't taking any anti-clotting medication.
About four years after they were treated, cancer recurred in only 9% of men taking an anti-clotting medication, compared with 22% of those who weren't taking the drugs.
After taking into account other risk factors for recurrence, taking an anti-clotting medication was associated with a 46% lower risk of recurrence, Choe says.
The benefit was most pronounced in men with high-risk aggressive cancers that had not yet spread (metastasized) at the time of radiation treatment. In this group, cancer recurred in 18% of men on anticoagulants vs. 42% of men not taking the drugs.
Cancer recurrence was defined as a rise in levels of prostate-specific antigen, or PSA. After radiation therapy, PSA levels usually drop to a stable and low level. Rising PSA levels are usually a sign of recurrence, Choe says.