Results from an international clinical trial, published in the Journal of Clinical Oncology, provide information about how three different approaches to the adjuvant (post-surgery) treatment of node-negative, premenopausal breast cancer affect quality of life and menstrual function.
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® (goserelin) is a medication known as a leuteinizing hormone releasing hormone (LHRH) agonist. In women Zoladex suppresses hormone production by the ovaries and reduces circulating estrogen levels.To evaluate various approaches to the adjuvant treatment of node-negative breast cancer in premenopausal women, an international group of researchers conducted a clinical trial among more than 1,000 women. After surgery women were assigned to one of three treatment groups: 1) six cycles of CMF (cyclophosphamide, methotrexate, and fluorouracil) chemotherapy; 2) 24 months of Zoladex; or 3) six cycles of CMF followed by 18 months of Zoladex.
Information about the effectiveness of each of these treatments was presented in a previous publication.Briefly, among women with estrogen receptor-negative breast cancer, treatment with CMF (with or without Zoladex) resulted in better cancer-free survival than treatment with Zoladex alone. Among women with estrogen receptor-positive breast cancer, there were no significant differences in cancer-free survival across treatment groups, although there was a suggestion that CMF followed by Zoladex may produce better outcomes than either CMF or Zoladex alone.
- By three months after the start of treatment, women treated with Zoladex alone reported worse mood and more hot flashes than women treated with CMF, but less nausea and vomiting.
- By six months after the start of treatment, women treated with Zoladex reported a greater ability to cope than women treated with CMF, and also continued to report less nausea and vomiting. There were no differences across study groups in the frequency of hot flashes at this point.
- By 36 months after the start of treatment, the only difference between study groups was in frequency of hot flashes, which were now more common in the women treated with CMF than in the women treated with Zoladex alone.
- Both treatment groups experienced amenorrhea (cessation of menstrual periods), but the timing and permanence of the amenorrhea differed by treatment. Women treated with Zoladex alone quickly stopped menstruating, but many women resumed menstrual periods after treatment with Zoladex ended. Women treated with CMF took longer to stop menstruating, but were less likely to resume menstruating after treatment was completed.
Studies such as this, which provide information about treatment effectiveness as well as treatment effect on quality of life and menstrual function, may help premenopausal women make more informed cancer treatment decisions.
 International Breast Cancer Study Group. Adjuvant Chemotherapy Followed by Goserelin Versus Either Modality Alone for Premenopausal Lymph Node-negative Breast Cancer: A Randomized Trial. Journal of the National Cancer Institute. 2003;95:1833-1846.
Bernhard J, Zahrieh D, Castiglione-Gertsch M et al. Impace of Adjuvant Chemotherapy Followed by Goserelin Compared with Either Modality Alone on Amenorrhea, Hot Flashes, and Quality of Life in Premenopausal Patients with Lymph Node-negative Breast Cancer: Results on the Effect of Age from the International Breast Cancer Study Group. Journal of Clinical Oncology [early online publication]. December 11, 2006.