DCIS is a non-invasive breast cancer involving only the cells lining milk ducts in the breast with no evidence that the disease has spread outside of these ducts  [2]. Until the 1980s, DCIS was treated by mastectomy. Today, options also include lumpectomy, or 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, Clinical Research, Oncology of AstraZeneca.

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 NSABP  [3] and published in The Lancet that included 1,804 women with DCIS who had a lumpectomy and radiation therapy. Half of those patients were prescribed tamoxifen and half received a placebo. After an average follow-up period of more than five years, the researchers found that the addition of tamoxifen to the treatment regimen significantly reduced the incidence of invasive breast cancer by 43 per cent among women assigned to Nolvadex (44 cases - Nolvadex, 74 cases placebo - p=0.004). Survival was similar in the placebo and Nolvadex groups.

AstraZeneca is a major international healthcare business engaged in the research, development, manufacture and marketing of ethical (prescription) pharmaceuticals and the supply of healthcare services. It is one of the top five pharmaceutical companies in the world with healthcare sales of $15 billion and leading positions in sales of gastrointestinal, oncology, anesthesia including pain management, cardiovascular, central nervous system (CNS) and respiratory products.