In a study presented today at the American Association for Cancer Research Third Annual International Conference on Frontiers in Cancer Prevention Research, scientists found that patients at all dose levels for toremifene had a lower cumulative incidence of cancer after 12 months of treatment, with the 20 mg dose contributing the greatest effect.
All participating patients had high-grade prostatic intraepithelial neoplasia or PIN, characterized by abnormal cells in the lining of the prostate ducts. Early research suggests that most patients with high-grade PIN will develop prostate cancer within 10 years, but more research is needed to confirm those findings.
"For men with high-grade PIN, the prospect of developing prostate cancer is a very real possibility," said Dr. Mitchell S. Steiner, chief executive officer with GTx, Inc. "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. A chemopreventive agent like toremifene is a first step toward the possibility of stopping prostate cancer before it starts and gives patients and doctors a chance to fight this pervasive disease."
In a multi-center, double-blind study, 514 patients with high-grade PIN and no cancer, determined by pre-study biopsies, were randomized to placebo or toremifene 20 mg, 40 mg or 60 mg given orally once a day. Patients were re-biopsied at six and 12 months.
During the study, 24.4 percent of patients taking 20 mg dose of toremifene were diagnosed with prostate cancer versus 31.2 percent of patients taking placebo. Among the patients who completed 12 months of treatment, the reduction in prostate cancer incidence was 48 percent for patients receiving 20 mg of toremifene compared to those in the placebo group.
According to the National Cancer Institute, prostate cancer is the most commonly diagnosed cancer in America among men. With an estimated 220,000 new cases diagnosed each year, one in every five men will get prostate cancer during his lifetime. African-American men are at special risk for the disease. In fact, the incidence rate in African-Americans is 60 percent higher than that in white males and double the mortality rate. An estimated 29,900 American men lose their lives to prostate cancer each year.
Founded in 1907, the American Association for Cancer Research is a professional society of more than 24,000 laboratory, translational, and clinical scientists engaged in all areas of cancer research in the United States and in more than 60 other countries. AACR's mission is to accelerate the prevention and cure of cancer through research, education, communication, and advocacy. Its principal activities include the publication of five major peer-reviewed scientific journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention. AACR's Annual Meetings attract more than 15,000 participants who share new and significant discoveries in the cancer field. Specialty meetings, held throughout the year, focus on the latest developments in all areas of cancer research.