Total Cumulative Dose of Chemotherapy and Breast Cancer Survival Rates
Posted: Wednesday, January 15, 2020
A study published in the Journal of the National Comprehensive Cancer Network found that reducing doses of the chemotherapy regimen FEC-D—fluorouracil, epirubicin, and cyclophosphamide followed by docetaxel—in the early stages of adjuvant chemotherapy had a negative effect on survival rates for patients with intermediate- and high-risk breast cancer. The study was conducted by Zachary Veitch, MSc, MD, FRCPC, of the University of Calgary’s Tom Baker Cancer Centre in Alberta, Canada.
“Medical oncologists should strive to deliver full-dose FEC when prescribing adjuvant FEC-D chemotherapy for breast cancer,” the investigators proposed. “Prospective evaluation of the optimal dose for docetaxel cycles in this regimen is warranted.”
The study included 1,302 women in Alberta, Canada, from 2007 to 2014. All of the women had stage I–III, hormone receptor–positive/negative, HER2-negative breast cancer and were treated with adjuvant FEC-D chemotherapy. Each patient received between four and six cycles of chemotherapy, including at least one cycle of docetaxel. Sixteen percent of the women (202 patients) received doses below 85% of the recommended amount; the remaining 1,100 women received doses at or above 85%.
After 5 years, the women in the low-dose group had lower rates of both disease-free survival (79.2% vs. 85.9% in the normal-dose group; P = .025) and overall survival (80.7% vs. 88.8%; P < .001). For disease-free survival, the trend was also seen in univariate (hazard ratio = 1.47) and multivariate analysis (hazard ratio = 1.45). The same held for overall survival in univariate (hazard ratio = 1.80) and multivariate analyses (hazard ratio = 1.50).
In addition, the study also found that lowering doses during the final three cycles of chemotherapy, when docetaxel was introduced, had a “minimal impact” on survival rates. Dosing changes during the first three cycles alone produced significantly lower disease-free and overall survival rates for the patients in the study.
Disclosure: The study authors’ disclosure information may be found at jnccn.org.