According to an early on-line article published in the Journal of Clinical Oncology, the anti-estrogen agent tamoxifen (Nolvadex®) following chemotherapy improves outcomes compared with chemotherapy alone in premenopausal women with early breast cancer.
Each year breast cancer is diagnosed in over 200,000 women in the US 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.
Historically, the most common hormonal treatment for estrogen receptor-positive breast cancer was an antiestrogen called Nolvadex® (tamoxifen). Nolvadex blocks estrogen receptors and prevents the estrogen-stimulated growth of breast cancer cells. There are now newer agents that help to prevent estrogen/progesterone from stimulating cancer cell growth.
The majority of women diagnosed with breast cancer are postmenopausal women. As a result, studies have been limited that evaluate the use of tamoxifen or other related agents in premenopausal women; hence, the value of these agents when used in premenopausal women has not been adequately established.
Researchers affiliated with the International Breast Cancer Study Group Trial 13-93 conducted a clinical trial to help assess the role of tamoxifen in premenopausal women with breast cancer.
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This trial included 1,246 premenopausal women who had early breast cancer that had spread to their axillary lymph nodes (node-positive cancer). Patients underwent the surgical removal of their cancer, followed by chemotherapy. Approximately half of the patients then underwent 5 years of treatment with tamoxifen, while the others had no further treatment.
Patients with hormone-positive breast cancer derived significant benefit from the use of tamoxifen.
- Cancer-free survival was improved by approximately 40% among women with hormone-positive breast cancer treated with tamoxifen, compared to those not treated with tamoxifen.
- Cancer-free survival was not improved with the use of tamoxifen among women with hormone-negative breast cancer.
- Patients with hormone-positive cancers who achieved amenorrhea (no menstrual cycles) while on chemotherapy had improved outcomes compared to those who did not experience amenorrhea while on chemotherapy, regardless of whether they were treated with tamoxifen.
The researchers concluded that the addition of tamoxifen following surgery and chemotherapy improves cancer-free survival among premenopausal women with hormone-positive, node-positive breast cancers. However, tamoxifen did not improve outcomes among women who had hormone-negative breast cancers.
These results give physicians further understanding of the value of tamoxifen or other related agents in the treatment of premenopausal women with breast cancer.
Reference: International Breast Cancer Study Group. Tamoxifen After Adjuvant Chemotherapy for Premenopausal Women With Lymph Node-Positive Breast Cancer: International Breast Cancer Study Group Trial 13-93. Journal of Clinical Oncology. 2006. Early on-line edition. DOI: 10.1200/JCO.2005.03.0783.