Taxane & cyclophosphamide vs anthracycline & taxane-based chemotherapy as adjuvant treatment for breast cancer: a pooled analysis of randomized controlled trials by the Hellenic Academy of Oncology

BACKGROUND: Adjuvant chemotherapy has an indisputable value for early breast cancer patients. Anthracycline and taxane-based regimens (TaxAC) have not been proven superior to taxane & cyclophosphamide (TC), a less toxic combination. Our objective was to estimate the cumulative evidence for non-inferiority of TC against TaxAC, in the adjuvant setting of patients with HER2-negative, breast cancer. RESULTS: Overall, 7,341 patients were included in this analysis. Superiority of TaxAC or non-inferiority of TC was not established either for the overall population (DFS HR, 1.11; 95% CI, 0.95–1.30; p = 0.18), or for the node-negative patients (HR, 1.05; 95% CI, 0.82–1.34; p = 0.71). A difference in DFS of 1.28% (TC DFS, 89.04%; 95% CI, 88%–90% & TaxAC DFS, 90.32%; 95% CI, 89%–91%) was found in favor of TaxAC. Lower risk of death was not established for either treatment regimen (OS-HR, 1.02; 95% CI, 0.82–1.25; p = 0.88). Overall, the toxicity profile favored TC. CONCLUSION: Although non-inferiority of TC was not proven, superiority of TaxAC is still questioned. The present analysis narrows the risk of recurrence between the treatment groups. Considering TC has a more favorable safety profile, the question as to which treatment regimen should be preferred under what circumstances, needs to be individualized according to patients’ characteristics and desires. METHODS: Treatment efficacy data from The ABC trials, the Plan B trial and a trial by the Hellenic Oncology Research group (HORG) were pooled. Disease free survival (DFS) and overall survival (OS) were scrutinized. A HR of 1.18 for TC versus TaxAC was chosen to demonstrate inferiority.