WASHINGTON (Reuters) - Taking a popular class of pain relievers that includes aspirin and ibuprofen lowers the levels of a protein in a man's blood that doctors use to screen for prostate cancer, U.S. researchers said on Monday.
But the researchers said it is unclear whether this means these men have a lower risk for developing prostate cancer or these medications may make it harder to detect prostate tumors with a common screening blood test.
The study involving 1,319 U.S. men age 40 and up found that those who took nonsteroidal anti-inflammatory drugs, known as NSAIDs, nearly every day had prostate specific antigen, or PSA, levels about 10 percent lower than men who did not take them.
PSA is a protein produced by cells in the prostate gland, and elevated levels in the bloodstream may indicate the presence of prostate cancer or other prostate conditions.
The researchers said it would be premature for men to take these drugs with the hope of lowering prostate cancer risk.
Many men over age 50, and some younger, in the United States and other countries get blood tests measuring PSA levels annually to screen for prostate cancer.
The study by researchers at the University of Rochester Medical Center in Rochester, New York, said the medications may mask a man's risk of getting prostate cancer by lowering PSA levels while his risk remains unchanged.
"If you're a guy who's close to the upper limit of normal (in PSA levels) or would have been over the upper limit and now you're under it because of this, that could certainly change whether or not you would be referred for a biopsy (to check for a tumor)," Dr Eric Singer, one of the researchers, said in a telephone interview.
NSAIDs are used by millions of people for headaches, minor pain, arthritis, lowering fever and reducing swelling.
Among them are aspirin, ibuprofen (Advil, Motrin and other brands) and naproxen (Aleve and other brands).
"While our results are consistent with other research that indicates that certain painkillers may reduce a man's risk of getting prostate cancer, the new findings are preliminary and don't prove a link," Edwin van Wijngaarden, another of the researchers, said in a statement.
The study, published in the American Cancer Society's journal Cancer, also found that men who regularly took acetaminophen (Tylenol) also had lower PSA levels. But the finding was not statistically significant because of the limited number of men in the study taking it.
There is a debate in the medical community about the value of PSA tests, with some saying that routine screening turns up many prostate tumors that pose no threat to a man's life and can lead to unnecessary prostate cancer treatment.
Experts are awaiting the results of clinical trials ongoing in the United States and Europe that may answer the question of whether PSA screening actually saves lives.
Prostate cancer is the second most commonly diagnosed form of cancer in men worldwide, with about 780,000 men diagnosed per year, and the sixth mostly deadly form in men, with about 250,000 deaths per year, the American Cancer Society said.
(Editing by Xavier Briand)