Comparison 1. Effect of trastuzumab.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Overall Survival (OS)‐ all studies	7	9935	Hazard Ratio (IV, Random, 95% CI)	0.66 [0.57, 0.77]
1.2 OS stratified by duration of trastuzumab administration	7		Hazard Ratio (IV, Random, 95% CI)	0.66 [0.57, 0.77]
1.2.1 <= 6 months	2		Hazard Ratio (IV, Random, 95% CI)	0.55 [0.27, 1.11]
1.2.2 > 6 months	5		Hazard Ratio (IV, Random, 95% CI)	0.67 [0.57, 0.80]
1.3 OS stratified by type of trastuzumab administration	7		Hazard Ratio (IV, Random, 95% CI)	0.66 [0.57, 0.77]
1.3.1 Sequential	2		Hazard Ratio (IV, Random, 95% CI)	0.85 [0.43, 1.67]
1.3.2 Concurrent	5		Hazard Ratio (IV, Random, 95% CI)	0.64 [0.53, 0.76]
1.4 Disease Free Survival (DFS) ‐ all studies	7	9935	Hazard Ratio (IV, Random, 95% CI)	0.60 [0.50, 0.71]
1.5 DFS stratified by duration of trastuzumab administration	7		Hazard Ratio (IV, Random, 95% CI)	0.60 [0.50, 0.71]
1.5.1 <= 6 months	2		Hazard Ratio (IV, Random, 95% CI)	0.31 [0.10, 0.96]
1.5.2 > 6 months	5		Hazard Ratio (IV, Random, 95% CI)	0.62 [0.52, 0.72]
1.6 DFS stratified by type of trastuzumab administration	7		Hazard Ratio (IV, Random, 95% CI)	0.60 [0.50, 0.71]
1.6.1 Sequential	2		Hazard Ratio (IV, Random, 95% CI)	0.71 [0.53, 0.95]
1.6.2 Concurrent	5		Hazard Ratio (IV, Random, 95% CI)	0.54 [0.44, 0.67]