Comparison 1. Overall survival.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Overall survival (all trials)	14	2116	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	0.96 [0.87, 1.07]
1.2 Overall survival (sensitivity analysis)	9	1229	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	0.95 [0.82, 1.09]
1.3 Overall survival (addition of 'less active' drug vs addition of 'more active' drug)	14		Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	Subtotals only
1.3.1 Addition of 'less active' drug	5	837	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	0.94 [0.81, 1.10]
1.3.2 Addition of 'more active' drug	9	1279	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	0.98 [0.85, 1.12]
1.4 Overall survival (adjusted dose in addition of drug arm vs no dose adjustment)	14		Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	Subtotals only
1.4.1 Adjusted dose in addition of a drug arm	9	1401	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	0.94 [0.83, 1.07]
1.4.2 Dose not adjusted in addition of a drug arm	5	715	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	1.00 [0.84, 1.18]
1.5 Overall survival (addition of anthracycline vs addition of non‐anthracycline)	14		Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	Subtotals only
1.5.1 Addition of an anthracycline	3	193	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	0.87 [0.61, 1.24]
1.5.2 Addition of a non‐anthracycline	11	1923	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	0.97 [0.87, 1.08]
1.6 Overall survival (addition of 1 agent vs addition of 2 or more agents)	14		Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	Subtotals only
1.6.1 Addition of 1 agent	10	1754	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	0.95 [0.85, 1.06]
1.6.2 Addition of 2 or more agents	4	362	Hazard Ratio (Exp[(O‐E) / V], Fixed, 95% CI)	1.05 [0.81, 1.35]