Long-Term Painkiller Use Linked to Kidney Cancer

Sept. 12, 2011 -- Long-term, regular use of non-aspirin anti-inflammatory painkillers raises the likelihood of developing kidney cancer by more than 50%, a study shows.

The study, published in the Archives of Internal Medicine, suggests men and women who take such drugs are equally at risk.

Some smaller studies had previously shown a tentative link between painkillers and kidney cancer. But study researcher Eunyoung Cho, ScD, assistant professor of medicine at Harvard Medical School, says this is the largest study to look at the relationship between the disease and the class of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs).

Drugs in this class include ibuprofen (Advil, Motrin), naproxen (Aleve), and Celebrex. Though aspirin is also an NSAID, no association has been found between kidney cancer and aspirin. 

Cho says that the overall risk is still quite low. She does not think that people should stop taking NSAIDs in the short term or that doctors should stop recommending them to patients who otherwise benefit from them.

Kidney cancer specialist Christopher W. Ryan, MD, who was not involved in the study, agrees.

"Occasional use for aches and pains is nothing to worry about," says Ryan, of Oregon Health and Science University's Knight Cancer Institute in Portland. "But one's risk of getting kidney cancer, even for a long-time user, is not high at all."

Measuring Risk of Long-Term Use

Cho and her colleagues analyzed the records of more than 77,000 women and nearly 50,000 men, all of whom were participants in one of two very large studies: the Nurses' Health Study and the Health Professionals Follow-up Study. The studies tracked the use of these medications for 16 years and 20 years, respectively.

Non-aspirin NSAIDs were used regularly at least two times per week by 19% of women and 6% of men.

The risk for both men and women who regularly took non-aspirin NSAIDs increased by 51% during the years analyzed. But a person's overall risk of getting kidney cancer is still small, as Ryan said. Of all the people in the study, 333 were diagnosed with kidney cancer. Still, the risk varied according to how long the medications were taken.

Those who took non-aspirin NSAIDs regularly for four to nine years had a 36% higher risk of kidney cancer compared to non-regular users. However, Cho says that that finding may have been due to chance. The only group at notable risk was made up of people taking them for more than 10 years. Their risk increased by nearly 300%.

"Not a large amount of people take them for that long," says Cho. "Short-term use is much more common."

Drug Industry Reaction

The Consumer Healthcare Products Association (CHPA), an industry group that represents over-the-counter drug manufacturers, says this class of drugs is both safe and effective when taken according to the label.