Mice studies have revealed that naproxen reduced the incidence of bladder cancer by 75 percent in rats, and intermittent dosing with naproxen (three weeks on the drugs, followed by three weeks off) was highly effective and likely to reduce gastric toxicity.
Naproxen is a non-steroidal anti-inflammatory drug (NSAID), and unlike most NSAIDs and aspirin, it has a lower cardiovascular risk and does increase the risk for gastric ulcers or bleeding. Researchers from the University of Michigan, the National Cancer Institute and the University of Alabama looked at naproxen' effects, with or without proton pump inhibitor omeprazole, on cancer prevention in a rat model of bladder cancer.
They found that naproxen reduced the incidence of bladder cancer by almost 75 percent, and omeprazole by itself did not affect the development of cancer but it also did not interfere with the effect of naproxen at preventing tumors. The rats who received naproxen alone or naproxen with omeprazole developed cancer at similarly low rates, while all rats who received omeprazole alone or no treatment developed bladder cancer.
Study author James Scheiman said, "Naproxen is a great candidate for chemoprevention. It comes with a risk of gastrointestinal side effects, but if you can mitigate that with a co-prescription, it's possibly an ideal chemoprevention drug." The researchers hope to plan a clinical trial to look at naproxen plus omeprazole in people at high risk of colon or other cancers.
The study has been published in the American Association for Cancer Research journal 'Cancer Prevention Research'.