Adjuvant therapy for breast cancer: who should get what?

Abstract

Breast cancer is the most common cancer diagnosed in women in the United States. More than 180,000 new cases of invasive breast cancer were projected in 2000, with more than 40,000 deaths expected.1 Nearly 90% of women will be diagnosed as having early-stage disease—cancer that is confined to the breast or extends locally into the axillary lymph nodes. Unfortunately, nearly 30% of women with cancer confined to the breast and 75% of women with nodal involvement will ultimately relapse.2 This observation affirms the presence of micrometastases, clinically occult tumor present after surgery with a potential to metastasize and confer both morbidity and mortality. Adjuvant treatment is the administration of additional therapy after primary surgery to kill or inhibit micrometastases. Primary surgery for breast cancer is accomplished by lumpectomy followed by whole-breast irradiation or by mastectomy. Adjuvant treatment may include local irradiation after mastectomy, systemic therapy with cytotoxic chemotherapy, or endocrine therapy. For the first time, a decrease was noted in breast cancer mortality in the United States and the United Kingdom, a welcome trend likely due to the use of adjuvant treatments.3 Recent progress in adjuvant therapy includes adding newer agents to standard chemotherapy, defining the role of endocrine therapy, and applying novel technologies to detect microscopic disease. In November 2000, the National Institutes of Health published a consensus statement as a guide for physicians, patients, and the public on the use of adjuvant therapy in breast cancer (www.nih.gov/news/pr/nov2000/omar-03.htm). This statement specifically addresses who should receive adjuvant treatment, what factors to consider in making this decision, and what type of adjuvant treatment should be offered.