Breast cancer hormone drug might help prevent prostate cancer

May 15 2005

A hormonal drug used to fight breast cancer might help prevent abnormal prostate growths from turning into cancers.

A new study found that men who took low doses of the drug Toremifene for a year, cut their chances of developing prostate cancer in half.

Doctors say the signs are encouraging, but the findings now need to be tested in larger studies.

The news is exciting as this is the first time any drug has been shown to prevent a precancerous condition from forming a tumour.

As many as 50,000 men in the U.S. each year are diagnosed with such growths, and then suffer constant worry and frequent biopsies to see whether cancer has developed.

Dr. Len Lichtenfeld, deputy medical director of the American Cancer Society, which had no role in the research, says before this discovery there was nothing to offer such men.

Toremifene, brand name Acapodene, is used for treating advanced breast cancer. It selectively blocks some of the effects of estrogen, a hormone men have in much smaller quantities than women.

Prostate cancer prevention and treatment has focused for many years on blocking the male hormone, testosterone.

Dr. Harmon Eyre,the cancer society's medical director, says targeting estrogen opens up a new area.

Prostate cancer is the most common major cancer in the United States and more than 230,000 new cases and about 30,000 deaths from it are expected this year.

The study leader Dr. David Price, a Shrevesport, La., urologist, says that men who have abnormal growths called prostatic intraepithelial neoplasia, or PIN, have about a 30 percent chance of developing prostate cancer within a year and about a 65 percent chance within two years.

He says this is a significantly worse prognosis than patients with just an elevated PSA, a blood protein used to measure prostate cancer risk. He is a consultant for Memphis-based GTx, which sells toremifene and funded the study.

The study involved 514 men with growths, at 64 sites across the country, who were given either fake pills or 20, 40 or 60 milligrams of toremifene for a year. Biopsies were done at six months and a year after treatment started.

The report was presented at latest meeting of the American Society of Clinical Oncology.