Among premenopausal women with early breast cancer, the addition of Zoladex® (goserelin) to adjuvant treatment with radiation therapy and/or chemotherapy resulted in improved survival. These results were published in the European Journal of Cancer.
Each year breast cancer is diagnosed in over 200,000 women in the U.S. alone. Many of these breast cancers will be hormone receptor-positive, meaning that they are stimulated to grow by the circulating female hormones estrogen and/or progesterone.
The growth of estrogen receptor-positive breast cancer cells can be prevented or slowed by reducing the exposure to estrogen. In premenopausal women, who have high levels of estrogen produced by the ovaries, suppression of ovarian hormone production may improve breast cancer outcomes.
Zoladex is a medication known as a leuteinizing hormone releasing hormone (LHRH) agonist. It is used in the treatment of prostate cancer, and has also been approved for the treatment of advanced breast cancer in pre- and peri-menopausal women. In women, Zoladex suppresses hormone production by the ovaries and reduces circulating estrogen levels.
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To explore the use of Zoladex among premenopausal women with early breast cancer, an international group of researchers conducted a clinical trial among 2710 women. All women were under the age of 50 and had operable stage I or stage II breast cancer. Half the women were randomly assigned to receive standard treatment (surgery, with or without radiation therapy and/or chemotherapy), and half the women were randomly assigned to receive standard treatment plus Zoladex.
- After five years of follow-up, the probability of being alive and breast cancer-free was 74.6% among women treated with Zoladex and 69.4% among women in the comparison group.
- Women treated with Zoladex also had better overall survival. Five-year overall survival was 87.6% among women treated with Zoladex and 84.9% among women in the comparison group.
The researchers conclude that “the addition of [Zoladex] to standard adjuvant therapy is more effective than standard therapy alone in premenopausal women with early breast cancer.”
Premenopausal women with early breast cancer may wish to talk with their physician about the risks and benefits of participating in a clinical trial evaluating this or other promising therapeutic approaches. Sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov).
Reference: Baum M, Hackshaw A, Houghton J et al. Adjuvant Goserelin in Pre-Menopausal Patients with Early Breast Cancer: Results from the ZIPP Study. European Journal of Cancer. March 15, 2006. Early Online Publication.