Breast Cancer Drug May Block Prostate Cancer

The drug toremifene, currently used to treat breast cancer, shows promise as a preventive for prostate cancer, according to a study.

The study found that 12 months of treatment with the drug reduced the incidence of prostate cancer in men believed to be at high risk for the disease.

The Study

The study included 514 cancer-free men who had high-grade prostatic intraepithelial neoplasia (PIN), a condition characterized by abnormal cells in the lining of the prostate ducts. Early research suggests that men who have high-grade PIN are more likely to develop prostate cancer within 10 years, although further research is necessary to confirm these findings.

The men received either a placebo or daily oral doses of 20 milligrams (mg), 40 mg or 60 mg of toremifene. The men's prostates were checked after six and 12 months. The results showed that 24.4% of the men taking the 20-mg dose were diagnosed with prostate cancer within one year, compared with 31.2% of the men taking the placebo.

Of those who completed the 12 months of treatment, the men taking the 20-mg dose had a 48% reduction in the incidence of prostate cancer compared with the men taking the placebo.

"For men with high-grade PIN, the prospect of developing prostate cancer is a very real possibility," says Dr. Mitchell S. Steiner, chief executive officer at GTx Inc., which makes and markets toremifene.

"With no effective treatment options available, doctors and patients often feel defenseless against the onset of prostate cancer. Fortunately, these results offer a promising new preventive approach to prostate cancer treatment," Steiner says.