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Weekly paclitaxel improves survival in women with breast cancer
Women with breast cancer may experience improved overall survival with the addition of weekly paclitaxel to their standard adjuvant chemotherapy treatment.
Researchers from the Eastern Cooperative Oncology Group in Philadelphia and other institutions in the United States conducted a randomized trial of 4,950 women with axillary lymph node-positive or high-risk, lymph node-negative breast cancer to compare the efficacy of two adjuvant breast cancer therapies.
All patients received three-week intervals of four cycles of intravenous doxorubicin and cyclophosphamide. They were then randomly assigned to three-week intervals of intravenous paclitaxel or docetaxel (Taxotere, Sanofi Aventis) for four cycles or at one-week intervals for 12 cycles, according to the researchers.
Compared with patients assigned to paclitaxel at three-week intervals, those assigned to weekly paclitaxel had a 1.27 odds ratio for disease-free survival (P=.006); those assigned docetaxel every three weeks had a 1.23 OR (P=.02); and those assigned weekly docetaxel had a 1.09 OR (P=.29). Weekly paclitaxel was linked to improved overall survival (OR, 1.32; P=.01), compared with standard therapy.
In a subgroup analysis, the researchers found similar results in disease-free and overall survival among patients with tumors that expressed no human epidermal growth factor receptor type 2 protein, regardless of hormone receptor expression. – by Stacey L. Adams
NEJM. 2008;358:1663-1671.
We have two taxanes, docetaxel and paclitaxel and both have activity in breast cancer. This trial was designed to determine whether one drug was superior and if a weekly schedule vs. every three weeks was superior for either drug.
They discovered that the weekly paclitaxel was a superior arm of the four groups tested when overall survival was used as an endpoint. There has been considerable debate in the literature about whether the addition of a taxane, either docetaxel or paclitaxel, after a doxorubicin-containing regimen was necessary for women with estrogen receptor-positive tumors. In this particular trial, they found that benefit for paclitaxel was not dependent on estrogen receptor status. Weekly paclitaxel had benefit for both ER-positive and ER-negative patients.
A complicating factor is the use of paclitaxel in a dose-dense fashion. Previous adjuvant studies have suggested that every two-week paclitaxel given after AC (doxorubicin and cyclophosphamide) was superior to every three-week paclitaxel. Now that we have data showing weekly paclitaxel is superior to every three-week paclitaxel, it remains unknown whether a dose-dense paclitaxel regimen or a weekly paclitaxel regimen is superior. Moreover, the reported adjuvant trials using paclitaxel in an every three-week schedule or a dose-dense schedule suggest less benefit for ER-positive patients. This trial showed that, at least in a weekly regimen, estrogen receptor-positive patients also benefitted from paclitaxel.
– Douglas Yee, MD
HemOnc Today Editorial Board member