Single-agent paclitaxel has failed to demonstrate noninferiority, compared with doxorubicin and cyclophosphamide in patients with early-stage, operable breast cancer, although it did show significantly less toxicity.
The trial in 3,871 women, followed for a median of 6.1 years and treated with four or six cycles of each treatment, recorded a hazard ratio (HR) for relapse-free survival of 1.26, favoring the combination of doxorubicin and cyclophosphamide, with an upper-bound confidence interval of 1.48, which exceeded the upper confidence bound of 1.3.
Combination therapy was associated with an HR of 1.27 for overall survival, while the estimated absolute advantage of the doxorubicin and cyclophosphamide combination at 5 years was 3% for relapse-free survival (RFS) and 1% for overall survival (OS), investigators reported online June 16 in the Journal of Clinical Oncology.
"Because we were not able to demonstrate noninferiority for either RFS or OS, single-agent T [paclitaxel] cannot be recommended as a standard regimen for women with primary breast cancer and zero to three positive axillary nodes," wrote Dr. Lawrence N. Shulman of the Dana-Farber Cancer Institute, Boston, and colleagues (J. Clin. Oncol. 2014 June 16 [doi:10.1200/JCO.2013.53.7142]).
An accompanying editorial noted that the results of the trial provided potentially useful biologic information on adjuvant chemotherapy for breast cancer although the results had limited application in current practice as many women are now treated with both taxanes and anthracyclines.
"The observation that single-agent T [paclitaxel] is potentially worse than AC [doxorubicin and cyclophosphamide] does provide some push back against those who want to abandon anthracyclines in early-stage breast cancer," wrote Dr. Pamela J. Goodwin of the University of Toronto and colleagues, in the editorial (J. Clin. Oncol. 2014 June 16 [doi: 10.1200/JCO.2014.55.9344]).
The study was partly supported by grants from the National Cancer Institute. Authors declared a range of consultancy, honoraria and funding from the pharmaceutical industry.