SAN ANTONIO (AP) -- Robin Khadduri gets monthly shots of a drug that blocks the male hormone testosterone and is often used to treat prostate cancer.

But Khadduri doesn't have a prostate or much testosterone either. She and many other young women are getting the drug for breast cancer as part of a super-hormone treatment that new research suggests may improve their survival odds.

This chemical equivalent of ovary removal has one big advantage over surgery: it's not permanent, so it may preserve a woman's ability to have children.

In premenopausal women, the drugs suppress the pituitary gland, which produces hormones that control the ovaries and cause a woman to have a period every month. Side effects of this induced early menopause are similar to those of natural menopause -- hot flashes, night sweats, etc., according to new research presented at the San Antonio Breast Cancer Symposium, which ended Sunday.

Women like Khadduri, who fear cancer's return, consider that a small price to pay.

The drugs include triptorelin, goserelin, leuprolide and buserelin, sold as Lupron, Zoladex, Prostap and other brands.

Such drugs have been around for 20 years and are used more in Europe than in the United States, where attention has focused more heavily on chemotherapy, said V. Craig Jordan of Fox Chase Cancer Center in Philadelphia, the scientist who developed tamoxifen, a mainstay hormone drug for preventing cancer recurrence.

"This has been like tumbleweed slowing gaining momentum," he said of ovarian suppression.

The drugs are most often used in two situations:

- As an alternative to chemotherapy for women who have had surgery for small, hormone-fueled tumors and are considered at relatively low risk for recurrence.

- As a way to keep the ovaries suppressed in women whose periods return after temporarily stopping during chemotherapy.

"They call it 'chemopause,'" said Khadduri, who is getting triptorelin shots now. The 37-year-old mother of three from Needham, Mass., was found in January to have two small tumors that had spread to at least one lymph node but not extensively.

"The thing I liked about it is, it was not permanent," she said of the treatment. "It wasn't like I was having surgery to have my ovaries removed. If the side effects were too much, I could stop."

Her physician, Dr. Eric Winer of the Dana-Farber Cancer Institute in Boston, enrolled her in one of three large experiments currently under way to test this approach.

"It's the oldest of all treatments," but doctors still do not know how much benefit it gives or how best to use it, Winer said.

In the latest research, Jack Cuzick of the Wolfson Institute of Preventive Medicine in London combined results from more than a dozen studies involving 9,000 women from 1987 to 2001.

Those that tested ovary-suppressing drugs on top or in place of chemotherapy and standard hormone therapy with tamoxifen found a lower risk of recurrence after an average of seven years -- 24 percent versus 29 percent -- among women given the more intense treatment.

Such women also had a smaller risk of death -- 11 percent versus 13 percent.

A second report at the cancer conference reinforced the value of ovarian suppression.

Dr. Michael Gnant of the Medical University of Vienna in Austria reported that women whose periods did not return after chemotherapy had lower cancer relapse rates than those resuming menstruation.

"Additional hormone suppression may be advisable" to keep periods from returning, he said.

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