Weekly Paclitaxel Improves Breast Cancer Survival
The Bottom Line
A randomized clinical trial showed that weekly doses of the drug paclitaxel (Taxol®) following surgery and standard chemotherapy improves disease-free and overall survival in women with breast cancer.
The Whole Story
Adjuvant therapy for cancer is treatment given in addition to a patient's primary therapy. Adjuvant therapy can include chemotherapy, hormonal therapy, radiation therapy, targeted therapy, or a combination of these treatments.
For many years, adjuvant chemotherapy for breast cancer has included the use of an anthracycline drug, such as doxorubicin or epirubicin, in combination with the drug cyclophosphamide. More recently, patients have received additional chemotherapy with a member of the taxane family of drugs, such as docetaxel or paclitaxel, after they complete anthracycline-based chemotherapy. The use of taxane chemotherapy is based on the finding that this additional treatment could improve disease-free survival in women with operable breast cancer. On the basis of results from two large clinical trials, treatment with the drug paclitaxel, given every 3 weeks over a 12-week period, was established as a new standard of care for operable breast cancer following anthracycline-based adjuvant chemotherapy. However, questions remained about which taxane drug was most effective and the optimum treatment schedule for its administration.
A randomized phase III clinical trial involving 4,950 women explored these issues and tested the effectiveness of docetaxel and paclitaxel given as single agents once a week or every 3 weeks over a 12-week period. All of the women had previously undergone surgery followed by chemotherapy with doxorubicin and cyclophosphamide. Cancer had spread to at least one nearby lymph node in 88 percent of the women; 70 percent had tumors that were positive for hormone receptors (estrogen and/or progesterone receptors); and 19% had tumors that were positive for the protein HER2. The researchers found that:
- Treatment with paclitaxel once a week and docetaxel every 3 weeks resulted in statistically significant improvements in disease-free survival when compared with paclitaxel treatment given every 3 weeks.
- Weekly treatment with paclitaxel also resulted in a statistically significant improvement in overall survival when compared with paclitaxel treatment every 3 weeks.
- Overall, paclitaxel caused fewer side effects than docetaxel; however, peripheral neuropathy (grades 2, 3, and 4) was highest in the group treated with paclitaxel once a week.
The report of this trial was published in the New England Journal of Medicine in April 2008.
More summaries of selected scientific advances from NCI-supported research are available at http://www.cancer.gov/aboutnci/servingpeople/advances.