Summary: Recruitment begins today for a new trial that will weigh the effectiveness and side effects of two drugs aimed at preventing breast cancer. Researchers and cancer specialists at the University of British Columbia and the BC Cancer Agency are part of a huge North American network involved in the long-awaited Study of Tamoxifen and Raloxifene.

VANCOUVER - The Study of Tamoxifen and Raloxifene, STAR, one of the largest breast cancer prevention studies ever, is now recruiting volunteers at more than 400 centres across Canada, the United States and Puerto Rico. The study underway in B.C. is a partnership between the University of British Columbia (UBC) Division of Surgery and the BC Cancer Agency and its four cancer centres in Kelowna, Surrey, Vancouver and Victoria.

"We are excited about bringing this important study to the Vancouver area," says Urve Kuusk, M.D., principal investigator. "Women everywhere are at risk for breast cancer, and we are pleased that B.C. will have the chance to participate in this important study."

The trial will include 22,000 postmenopausal women at increased risk of breast cancer to determine whether the osteoporosis prevention drug raloxifene (Evista) is as effective in reducing the chance of developing breast cancer as tamoxifen (Nolvadex) has proven to be.

"The field of breast cancer prevention has enormous potential to reduce morbidity and mortality," says Dr. Charmaine Kim-Sing, medical leader of the Hereditary Cancer Program and head of breast cancer prevention initiatives at the BC Cancer Agency. "Many of the women I met through the first study entered the trial because they had been personally touched by breast cancer - through a mother or sister. True, they were in a higher risk group, but their motivation seemed to be that they wanted to do something to advance the knowledge of breast cancer prevention." Other investigators in B.C. are UBC's Dr. Robert Baird and BC Cancer Agency's Drs. Sharon Allan, Susan Ellard, Randall Fairey, Brian Norris, Melanie Reed and Lorna Weir.

UBC Breast Clinic is part of the National Surgical Adjuvant Breast and Bowel Project (NSABP), the network of research professionals that will conduct STAR, which is supported by the National Cancer Institute (NCI). NSABP chairman Norman Wolmark, M.D. says "studies of raloxifene suggest it has the potential to prevent breast cancer. The only way to prove that potential is to do a clinical trial in which the risks and benefits of raloxifene are directly compared with the risks and benefits of tamoxifen."

Tamoxifen was shown to reduce the chance of developing breast cancer by about half in the Breast Cancer Prevention Trial (BCPT), a study of more than 13,000 premenopausal and postmenopausal women at high risk of breast cancer. Results of this trial were announced a year ago (April 1998) and published in the Journal of the National Cancer Institute in September 1998. In the BCPT, half the women took tamoxifen and half took a placebo (an inactive pill that looked like tamoxifen). Participants taking tamoxifen also had fewer fractures of the hip, wrist and spine than women taking the placebo.

However, the drug increased the women's chances of developing four potentially life-threatening health problems: endometrial cancer (cancer of the lining of the uterus); deep vein thrombosis (blood clots in large veins); pulmonary embolism (blood clot in the lung); and possibly stroke. The U.S. Food and Drug Administration (FDA) approved the use of tamoxifen to reduce the incidence of breast cancer in women at increased risk in October 1998.

Dr. Leslie Ford, associate director for clinical research in NCI's Division of Cancer Prevention, says "tamoxifen is a medically proven intervention, but it is not perfect. Women who are at an increased risk of breast cancer need options for preventing this disease with a minimum of side effects, and STAR is a concerted effort to find one." Ford is responsible for all aspects of NCI's involvement in STAR.

Information about the safety of raloxifene is limited compared to the data available on tamoxifen. Raloxifene was approved in December 1997 by the FDA and in November 1998 by Canada's Health Protection Branch to prevent osteoporosis and has been in clinical trials for about five years. Tamoxifen has been approved to treat women with breast cancer for more than 20 years and has been in clinical trials for about 30 years. Women taking raloxifene in studies of osteoporosis have had an increased chance of developing a deep vein thrombosis or pulmonary embolism similar to the risk seen with tamoxifen. In these studies, raloxifene did not increase the risk of endometrial cancer. An important part of STAR will be to compare the long-term safety of raloxifene and tamoxifen in women at increased risk of breast cancer.

Women who participate in STAR must... 

• be postmenopausal, 
• be at least 35 years old, 
• have an increased risk of cancer as determined by their age, family history of breast cancer, personal medical history, age at first menstrual period and age at first live birth, 
• participate in a process known as informed consent, during which they will learn about the potential benefits and risks of tamoxifen and raloxifene before deciding whether to participate in STAR. Once a woman chooses to participate, she will be randomly assigned to receive either 20 mg tamoxifen or 60 mg raloxifene daily for five years and will have regular follow-up examinations, including mammograms and gynecologic exams.

The maker of tamoxifen, Zeneca Pharmaceuticals, Wilmington, Del., and the maker of raloxifene, Eli Lilly and Company, Indianapolis, Ind., are providing their drugs for the trial without charge. Eli Lilly and Company has also given NSABP a $36-million grant to defray recruitment costs at the participating centers and to help local investigators conduct the study.

For more information about STAR, call Lynn Fearn or Janet Mackie at 822-7997 at the UBC Breast Clinic. Or, visit NSABP's web site at http://www.nsabp.pitt.edu/ or NCI's clinical trials web site at http://cancertrials.nci.nih.gov

The BC Cancer Agency provides a comprehensive cancer control program for the people of British Columbia by working with community partners to deliver a range of oncology services, including prevention, early detection, diagnosis and treatment, research, education, supportive care, rehabilitation and palliative care. The BC Cancer Research Centre conducts research into the causes and cures for cancer. The BC Cancer Foundation has a mandate to raise funds to support the work of the Agency and Research Centre, for a world without fear of cancer.

For more information, please call Francine Gaudet:
Ph: 604.877.6107
Fax: 604.877.6146
Public Relations.