Popular Drugs Found to Decrease PSA Levels
Two of the most common classes of medication — statins and nonsteroidal anti-inflammatory drugs (NSAIDs) — may compromise cancer screenings by lowering serum prostate-specific antigen (PSA) levels, according to two studies.
Researchers at Duke University in Durham, N.C., conducted a longitudinal study of 1,214 men (median age 60.3 years) who filled statin prescriptions to lower LDL between 1990 and 2006. The majority of participants (95%) used simvastatin (Zocor), and the most common initial dose was 20 mg, according to a report in the Journal of the National Cancer Institute (2008;100:1511-1518).
Serum PSA levels declined an average of 4.1% after statin therapy was started. The association appeared to be direct. Every 10% decrease in LDL was accompanied by a 1.64% decrease in PSA. In addition, men whose PSA prior to statin therapy was higher than 2.5 ng/mL and who were in the top quartile for LDL reduction (greater than 41%) experienced a 17.4% PSA decline.
This effect “may complicate prostate cancer screenings because cancers may be missed due to the lower PSA levels, and this fact should be kept in mind when evaluating men taking statins,” the authors observed.
In the other study, researchers at Vanderbilt University in Nashville examined the effect of NSAID use and PSA levels in 1,277 participants in the Nashville Men's Health Study. Subjects were older than 40 years and scheduled for diagnostic prostate biopsy. About 46% of these men reported taking an NSAID, including 37% who specified they were taking aspirin.
“Many men take NSAIDs for their cardiovascular health, so we need to know whether these medications reduce prostate cancer risk or simply reduce PSA, which would then be even less reliable as a marker of prostate cancer risk,” said lead investigator Jay H. Fowke, PhD, an assistant professor of medicine at Vanderbilt.