Comparison 1. No axillary surgery versus full axillary surgery.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 All‐cause mortality (radiotherapy subgroups)	10	3849	Hazard Ratio (95% CI)	1.06 [0.96, 1.17]
1.1 no radiotherapy	1	773	Hazard Ratio (95% CI)	0.96 [0.80, 1.15]
1.2 radiotherapy	9	3076	Hazard Ratio (95% CI)	1.11 [0.98, 1.25]
2 All‐cause mortality (extra treatment for positive node subgroups)	10	3849	Hazard Ratio (95% CI)	1.06 [0.96, 1.17]
2.1 additional treatment for node‐positive patients	3	1174	Hazard Ratio (95% CI)	1.51 [1.09, 2.09]
2.2 no specific additional treatment for node‐positive patients	7	2675	Hazard Ratio (95% CI)	1.02 [0.92, 1.13]
3 Locoregional recurrence (radiotherapy subgroups)	4	20863	Hazard Ratio (95% CI)	2.35 [1.91, 2.89]
3.1 no radiotherapy	1	7284	Hazard Ratio (95% CI)	2.94 [2.05, 4.23]
3.2 radiotherapy	3	13579	Hazard Ratio (95% CI)	2.11 [1.64, 2.72]
4 Locoregional recurrence (extra treatment for positive‐node subgroups)	4	20863	Hazard Ratio (95% CI)	2.35 [1.91, 2.89]
4.1 additional treatment for node‐positive patients	1	4171	Hazard Ratio (95% CI)	1.10 [0.69, 1.75]
4.2 no specific additional treatment for node‐positive patients	3	16692	Hazard Ratio (95% CI)	2.83 [2.25, 3.57]
5 Distant metastasis	2	946	Hazard Ratio (95% CI)	1.06 [0.87, 1.30]
5.1 no radiotherapy	1	727	Hazard Ratio (95% CI)	1.10 [0.89, 1.35]
5.2 radiotherapy	1	219	Hazard Ratio (95% CI)	0.64 [0.28, 1.42]
6 Lymphoedema (≥ 12 months postop) ‐ fixed‐effect model	4	1714	Odds Ratio (M‐H, Fixed, 95% CI)	0.31 [0.23, 0.43]
6.1 additional treatment for node‐positive patients	1	532	Odds Ratio (M‐H, Fixed, 95% CI)	0.07 [0.02, 0.22]
6.2 no additional treatment for node‐positive patients	3	1182	Odds Ratio (M‐H, Fixed, 95% CI)	0.39 [0.28, 0.54]
7 Lymphoedema (≥ 12 months postop) ‐ random‐effects model	4	1714	Odds Ratio (M‐H, Random, 95% CI)	0.22 [0.08, 0.57]
7.1 additional treatment for node‐positive patients	1	532	Odds Ratio (M‐H, Random, 95% CI)	0.07 [0.02, 0.22]
7.2 no additional treatment for node‐positive patients	3	1182	Odds Ratio (M‐H, Random, 95% CI)	0.40 [0.28, 0.55]
8 Arm or shoulder movement impairment (≥ 12 months postop)	5	1495	Odds Ratio (M‐H, Fixed, 95% CI)	0.72 [0.49, 1.05]
8.1 radiotherapy	5	1495	Odds Ratio (M‐H, Fixed, 95% CI)	0.72 [0.49, 1.05]
9 Pain (≥ 12 months postop)	1		Odds Ratio (M‐H, Fixed, 95% CI)	Totals not selected
9.1 radiotherapy	1		Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
10 Paraesthesia (≥ 12 months postop)	1		Odds Ratio (M‐H, Fixed, 95% CI)	Totals not selected
10.1 radiotherapy	1		Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
11 Delayed healing	1		Odds Ratio (M‐H, Fixed, 95% CI)	Totals not selected
11.1 radiotherapy	1		Odds Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
12 Skin graft	1		Odds Ratio (M‐H, Random, 95% CI)	Totals not selected
12.1 radiotherapy	1		Odds Ratio (M‐H, Random, 95% CI)	0.0 [0.0, 0.0]
13 All‐cause mortality (allocation concealment subgroups)	10	3849	Hazard Ratio (95% CI)	1.06 [0.96, 1.17]
13.1 adequate allocation concealment	4	1442	Hazard Ratio (95% CI)	0.98 [0.81, 1.18]
13.2 unclear or inadequate allocation concealment	6	2407	Hazard Ratio (95% CI)	1.09 [0.97, 1.23]