Certain types of pain-relieving drugs may help current and former smokers lower their risk of developing lung cancer, according to a new study.

Joshua Muscat, PhD, from the American Health Foundation in Valhalla, New York, and colleagues compared more than 1,000 patients with lung cancer to another 1,000 patients without cancer from the same hospitals. Most of the cancer patients (more than 90%) were current or former smokers, and slightly more than half (55%) of the patients without cancer were current or former smokers.

The researchers found that the smokers without lung cancer were more likely to have regularly taken aspirin or related pain relievers known as non-steroidal anti-inflammatory drugs (NSAIDs).

The researchers reported their findings in the American Cancer Society journal Cancer (Vol. 97, No. 7: 1732-1736).

NSAIDs are a group of drugs that have long been used for their pain relieving and anti-inflammatory properties, such as in treating arthritis. Examples of commonly used NSAIDs include aspirin, ibuprofen, ketoprofen, and naproxen. (Acetaminophen, another common pain reliever, is not an NSAID.)

In recent years, however, doctors have studied their use in preventing and treating other conditions as well, such as heart disease. Some studies have suggested they may even play a role in reducing the risk of colorectal cancer. Two recent studies showed that regular aspirin use reduced the risk of developing colorectal polyps, which are thought to be cancer precursors. The FDA has already approved another NSAID, celecoxib, for a small group of people with an inherited tendency to develop such polyps.

But the usefulness of NSAIDs in reducing the risk of most other cancers remains largely unknown. With regard to lung cancer, some studies have found a benefit from aspirin use, while others have not.

Muscat and colleagues interviewed 1038 lung cancer patients and 1002 patients admitted to the hospital for reasons other than cancer, asking them about their use of pain relievers.

The researchers found that smokers and former smokers who used aspirin or other NSAIDs at least three times a week for a year or more were significantly less likely to have developed lung cancer. The effect appeared to be stronger for men than for women, especially among current smokers.

No such advantage was found among those who did not smoke, although lung cancer is relatively rare in nonsmokers to begin with.

Noting that lung cancer is the leading cause of cancer deaths, the study authors concluded, “[T]he possibility that commonly used pain medication can reduce the rates should be explored further.”

The authors pointed out, however, that previous studies looking at NSAIDs and lung cancer risk have had conflicting results.

An expert from the American Cancer Society (ACS) agrees that further research is needed before NSAIDs can be recommended for reducing the risk of lung or other cancers.

“The results are certainly interesting, but they need to be confirmed by other studies,” says Rick Alteri, MD, a medical editor with ACS. “Unfortunately, NSAIDs are not without side effects. May people on NSAIDs experience gastrointestinal or other problems, and some, such as aspirin, can cause bleeding. More evidence that the benefits outweigh the possible risks will be needed before any recommendations can be made.”

“In the meantime, close to 90% of lung cancers—and varying amounts of some other common cancers—can be attributed to tobacco use,” Alteri continued. “Without a doubt, the best way to reduce the risk of lung cancer is to stop smoking.”