One hundred and twenty-three trials were included (more than 100,000 participants). A large number of analyses were conducted (the main results as reported by the authors are presented here).
Trials that added four separate cycles of a taxane to a fixed anthracycline control extended treatment duration demonstrated a reduction in breast cancer mortality (RR 0.86, SE 0.04, p = 0.0005). There were no significant differences when extra cycles of a taxane were counterbalanced in control groups by extra cycles of other cytotoxic drugs.
Trials that compared standard 4AC (four cycles of doxorubicin and of cyclophosphamide three-weekly) and standard CMF had similar results. Anthracycline-based regimens with substantially higher cumulative dosage than standard 4AC were found to be superior to standard CMF (RR 0.78, SE 0.06). Trials versus no chemotherapy suggested greater mortality reductions with CAF (cyclophosphamide, doxorubicin, fluorouracil) (RR 0.64, SE 0.09) than with standard 4AC (RR 0.78, SE 0.09) and standard CMF (RR 0.76, SE 0.05).
In all analyses that involved taxane-based or anthracycline-based regimens, reductions were little affected by age, nodal status, tumour diameter or differentiation and oestrogen receptor status or tamoxifen use. Overall mortality differences were similar to those for breast cancer mortality.