Update in Oncology

Breast Cancer

Dose-Dense Therapy Improved Clinical Outcomes in Node-Positive Breast Cancer

The standard of care for patients with node-positive breast cancer involves administering a predefined course of adjuvant chemotherapy (for patients without clinically significant comorbid conditions) after primary surgery. This approach aims to eradicate any micrometastic disease that may be present and thus increase cure rates.

Almost all North American patients with a breast tumor 1 cm or greater at presentation are currently offered some form of adjuvant chemotherapy, which typically contains drugs such as anthracyclines and taxanes. Patients who have hormone receptor–positive breast cancer, defined as either estrogen receptor–positive or progesterone receptor–positive, are also offered adjuvant hormonal use, typically tamoxifen for premenopausal women and tamoxifen or aromatase inhibitors for postmenopausal women.

This standard of care for the adjuvant treatment of breast cancer is the result of intense investigation during the last 20 years and is continually evolving. Cure rates for early-stage, node-negative breast cancer are 80% to 90% at 10 years. However, node-positive patients who are followed long enough may continue to relapse at a rate of 40% to 50% at 10 years; as a result, the search for better adjuvant treatments continues. To shorten discovery time, investigators design large adjuvant studies that generate enough outcomes (deaths and relapses) in the first 3 to 4 years to make confident conclusions about relatively small treatment effects. For a common disease that causes more than 40 000 deaths yearly in North America, even small differences in overall survival can have a large impact on public health.

This study compared standard (every 3 weeks) chemotherapy with dose-dense (every 2 weeks) chemotherapy for node-positive patients with breast cancer. The study also tested sequential (doxorubicin …