A drug used to treat breast cancer may also help Prostate cancer from developing in men who have precancerous lesions, researchers reported on Saturday.

Men with a condition called prostatic intraepithelial neoplasia, or PIN, which progresses to cancer in a year in 30 percent of cases, usually have to wait it out and hope. But a drug called toremifene, developed by Memphis, Tennessee-based GTx, Inc. under the brand names Acapodene and Fareston, cuts that rate in half.

“This is the first time that a drug has shown promise for lowering the incidence of prostate cancer in men with PIN,” said Dr. David Price of Regional Urology, a clinic in Shreveport, Louisiana, who led the study.

If a man has a high reading of prostate specific antigen, or PSA, in his blood, or if he has symptoms of an enlarged prostate, he sometimes has a biopsy - a sample of the prostate - taken to see if it is cancerous.

About 10 percent of men who get biopsies are diagnosed with PIN. The condition is comparable to a polyp in the colon that may turn into a colon cancer tumor, or a condition called ductal carcinoma in situ, which often progresses to breast cancer.

“As a clinical urologist, when I see men and I diagnose them with Prostate cancer, I have good options for them. I can offer them radiation therapy or surgery,” Price told a news conference.

“When they are diagnosed with PIN I have to tell them, ‘You have a one in three chance of developing prostate cancer, but I have no option but to follow you.’ It is distressing for the patients and their families.”

These men have to get repeated biopsies, and they have a 15 times greater risk of developing prostate cancer over their lifetimes than most men.

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Laboratory tests suggested toremifene might help. It is a selective estrogen/androgen receptor modulator or SERM, similar to other drugs used to treat breast cancer, and it interferes with how hormones affect cancer cells.

In a trial funded by GTx, Price’s team tested toremifene in 514 patients who had high-grade PIN.

After a year of taking the pills daily, the men who got toremifene were 48 percent less likely to be diagnosed with prostate cancer than the men given placebos, Price told a meeting of the American Society of Clinical Oncology in Orlando.

The company has started a larger, phase III trial in 1,500 men.

Because the drug is already approved for use in treating breast cancer, its safety is not in question, Price said.

Even if the drug is delaying prostate cancer instead of preventing it, that could be good, Price said.

Prostate cancer usually is a slow-growing cancer, so if men can push their diagnosis back until they are elderly, they will be unlikely to die of the prostate cancer before they die of something else.

Prostate cancer is the third most common cancer worldwide. Every year, more than 200,000 U.S. men are diagnosed with the disease and it will kill 30,000 in 2005, according to the American Cancer Society.

Other studies presented at the conference hinted at new options for men who have prostate cancer.

A study supported evidence that Dendreon Corp.‘s Provenge, a so-called therapeutic vaccine that stimulates the immune system to attack tumors, could help advanced prostate cancer patients live a few months longer.

Therion Biologics reported its targeted prostate cancer vaccine Prostvac may help control prostate cancer in men whose tumors have come back or spread after initial treatment.