Abortion pill may battle brain tumors.

The controversy surrounding RU486 (mifepristone) centers on its use as an abortion-inducing drug. Early safety testing suggests that this so-called abortion pill may have another use, this time as a treatment for a type of brain tumor.

Researchers led by Steven M. Grunberg, an oncologist at the University of Southern California School of Medicine in Los Angeles, recruited 19 women and nine men suffering from meningioma, a slow-growing, noncancerous tumor. Treatment typically consists of surgery to remove the tumor, which affects the tissue lining the brain and spinal cord. But in some cases, surgery is too risky. In such cases, the tumor continues to grow and can cause blindness, paralysis, and seizures. All 28 people in the study had inoperable tumors.

Cancer specialists have observed that meningiomas occur more frequently in women than in men. Symptoms of these tumors often worsen during pregnancy. when a woman's body produces increased amounts of the sex hormone progesterone. Indeed, meningioma cells often contain progesterone receptors, Grunberg says. Men also produce progesterone.

These observations have led researchers to hypothesize that progesterone fuels the growth of such tumors. Grunberg's team wondered whether pristone, which blocks progesterone receptors, would slow the tumor's progress. To test that theory. they gave each of the 28 patients low-dose mifepristone daily for approximately a year.

It's too early to tell whether mifepristone will prove an effective tumor fighter, but initial results are encouraging. At the American Cancer Society's (ACS) 35th Science Writers Seminar, held in San Diego last month, Grunberg reported that eight of the 28 people benefited from the treatment. In six of these patients, the tumors shrank slightly during the trial. A seventh patient: who was nearly blind in one eye, reported dramatic vision improvement in that eye after treatment with mifepristone, Grunberg says, and another had less dramatic vision improvement.

So far, side effects associated with the drug include fatigue, hot flushes, some thinning of the hair, and a rash.

The team has already launched a larger study, comparing mifepristone to a placebo pill in a double-blind, randomized trial of 200 people with meningioma.