AstraZeneca announced recently that the US Food and Drug Administration (FDA) has approved use of its breast cancer drug tamoxifen(Drug information on tamoxifen) (Nolvadex) to reduce the risk of invasive breast cancer in women with ductal carcinoma in situ (DCIS) following breast surgery and radiation. Tamoxifen is the first medication to be approved for DCIS, which accounts for nearly 20% of all newly diagnosed breast cancer cases.
The approval of tamoxifen to reduce the risk of invasive breast cancer in women with DCIS is an important advance in the management of breast cancer, said Monica Morrow, md, director, Lynn Sage Breast Center and professor of surgery, Northwestern University Medical School. As more women have routine mammograms, breast cancer is being detected much earlier. These women now can take a drug that, when added to breast surgery and radiation, has been proven to reduce the likelihood that the cancer will spread or recur.
Effective Across All Stages
Until the 1980s, DCIS was treated by mastectomy. Treatment options, at present, include lumpectomy, and lumpectomy plus radiation therapy.
The effectiveness of Nolvadex has now been proven across all stages of the breast cancer continuum, from risk reduction in women at high risk to the treatment of advanced breast cancer, said Jerry P. Lewis, MD, senior director of AstraZenecas clinical research, oncology.
AstraZeneca filed a supplemental new drug application with the FDA for the DCIS indication in December 1999, and was granted priority review in March 2000. The FDA submission was based on data from a study conducted by the National Surgical Adjuvant Breast and Bowel Project and published in The Lancet (353:1993-2000, 1999).
The placebo-controlled study included 1,804 women with DCIS who had a lumpectomy and radiation therapy. After an average follow-up of more than 5 years, the researchers found that the addition of tamoxifen to the treatment regimen reduced the incidence of invasive breast cancer by 43% (44 vs 74 cases in the tamoxifen and placebo groups, respectively; P = .004). Survival was similar in the two groups.
In clinical trials of tamoxifen therapy, the risk of endometrial cancer and blood clots in the lungs and legs increased approximately two to three times compared to placebo, although each event occurred in fewer than 1% of the women studied. Stroke, cataracts, and cataract surgery also occur more frequently with tamoxifen than with placebo. More common side effects of the drug are vaginal discharge and hot flashes.