MONDAY, April 14 (HealthDay News) -- Two widely used drugs -- one lowers cholesterol and one is an anti-inflammatory -- may be useful in controlling prostate cancer.

New research being presented at the American Association for Cancer Research annual meeting in San Diego finds that the painkiller Celebrex and the statin Lipitor, when used together or alone, can stop early prostate cancer before it becomes deadly.

The study was conducted in mice so the idea isn't yet ready for clinical use, but experts said these preliminary results did look promising.

"They need to come up with the molecular mechanics and then take it back to clinical trials," said Dr. K. Scott Coffield, a professor of surgery at Texas A&M Health Science Center College of Medicine and a urologist-oncologist at Scott & White. "It's early but it's interesting and that's wonderful."

"It's very intriguing and it gives some clinical data, but it's not enough to start recommending these medications for people who don't need them for other reasons," added Dr. Ronald D. Ennis, director of radiation oncology at St. Luke's Roosevelt Hospital, Continuum Cancer Centers, in New York City.

Prostate cancer is the second-leading cancer killer in men in the United States. In the early stages, prostate tumors depend on androgen (male) hormones such as testosterone to grow. As such, early treatment typically involves interfering with these hormones but these therapies eventually lose their effectiveness. Tumors that are dependent on androgen are typically less aggressive than later tumors that don't rely on androgen.

Epidemiological studies have suggested that statins (such as Lipitor) and nonsteroidal anti-inflammatory drugs (such as Celebrex) may be able to stop the progression from an early cancer to a later, more aggressive malignancy.

This study aimed to delay the progression of androgen-dependent tumors to androgen-independent tumors, thus allowing doctors more time to administer anti-hormone therapy. Anti-androgen therapy is less toxic than many other cancer therapies, as are Lipitor and Celebrex.

"Comparing complications for many anti-cancer treatments, these drugs generally would be very safe," Ennis said. (Celebrex, a cox-2 inhibitor, is the only drug in this class still on the market in the United States; two others, Vioxx and Bextra, were withdrawn because of safety issues).

In the study, the investigators first cultured prostate tumors in mice, then added in either Lipitor or Celebrex, and then the combination of the two drugs.

All three approaches inhibited cancer growth. Interestingly, however, the combination of Lipitor and Celebrex at lower doses than when given individually resulted in a greater effect, the team found.

"It had a pretty substantial effect with this combination," said study senior author Allan Conney, director of the Susan Lehman Komen Laboratory for Cancer Research at the Ernest Mario School of Pharmacy of Rutgers University, in New Brunswick, N.J.

"We're hoping that this can be extrapolated to humans," Conney added. "There's a need to do a clinical trial on this combination of Lipitor and Celebrex to see if it can prolong the time that it takes to convert the androgen-dependent tumors to androgen-independent tumors, which are the more severe kind."

As of now, it's unclear why Lipitor and Celebrex are having this effect on prostate tumors.

Ennis doubted it was a cholesterol issue. "Statins as a group must have another effect beyond lowering cholesterol," he said. "They're known to have some anti-inflammatory effects but what they're doing to cancer isn't known yet. Once we figure that out, we may be able to develop better drugs that do the same thing."

"That's very exciting but not yet enough to start prescribing this for prostate cancer," Ennis added.

More information

There's more on prostate cancer at the American Cancer Society.