Table 6. Standard Adjuvant Chemotherapy Regimens for Stage I, II, IIIA, and Operable IIICHER2/neuNon-Overexpressing Breast Cancer continued...
Adjuvant Chemotherapy 2000s to Present: The role of adding taxanes to adjuvant therapy
A number of trials have addressed the benefit of adding a taxane (paclitaxel or docetaxel) to an anthracycline-based adjuvant chemotherapy regimen. A literature-based meta-analysis of 13 such studies demonstrated that the inclusion of a taxane improved both DFS and OS (DFS: HR, 0.83; 95% CI, 0.79–0.87; P < .0001; OS: HR, 0.85; 95% CI, 0.79–0.91; P < .0001).[Level of evidence: 1iiA] Five-year absolute survival differences were 5% for DFS and 3% for OS in favor of taxane-containing regimens. There were no differences in benefit observed in patient subsets defined by nodal status, hormone receptor status, or age/menopausal status. There was also no apparent difference in efficacy between the two agents. However, none of the studies reviewed involved a direct comparison between paclitaxel and docetaxel.
An Eastern Cooperative Oncology Group–led intergroup trial (E1199 [NCT00004125]) involving 4,950 patients compared, in a factorial design, two schedules (weekly and every 3 weeks) of the two drugs (docetaxel vs. paclitaxel) following standard-dose AC chemotherapy given every 3 weeks.[Level of evidence: 1iiA] There was no difference observed in the overall comparison with regard to DFS of docetaxel to paclitaxel (odds ratio [OR], 1.03; 95% CI, 0.91–1.16; P = .61) or between the 1-week and 3-week schedules (OR, 1.06; 95% CI, 0.94–1.20; P = .33). However, there was a significant interaction between the drug administered and schedule for both DFS (0.003) and OS (0.01). Thus, compared with paclitaxel given every 3 weeks, paclitaxel given weekly improved both DFS (OR, 1.27; 95% CI, 1.01–1.57; P = .006) and OS (OR, 1.32; 95% CI, 1.02–1.72; P = .01). Docetaxel given every 3 weeks was also superior in DFS to paclitaxel given every 3 weeks (OR, 1.23; 95% CI, 1.00–1.52; P = .02), but the difference was not statistically significant for OS (OR, 1.13; 95% CI, 0.88–1.46; P = .25). Docetaxel given weekly was not superior to paclitaxel given every 3 weeks. There was no stated a priori basis for expecting that varying the schedule of administration would have opposite effects for the two drugs. Thus, these results are hypothesis generating and should be confirmed.