Table 3.

Unadjusted side effects in the sample before and after matching

	Table 2 Before matching					Table 2 After matching
	No SLNB N = 13,106		SLNB N = 2409		χ 2	No SLNB N = 4718		SLNB N = 2409		χ 2
	N	%	N	%	p value	N	%	N	%	p value
Any of below	1476	11.3	404	16.8	< 0.001	534	11.3	404	16.8	< 0.001
Lymphedema	57	0.4	60	2.5	< 0.001	23	0.5	60	2.5	< 0.001
Wound infection	1290	9.8	296	12.3	< 0.001	453	9.6	296	12.3	< 0.001
Seroma	421	3.2	153	6.4	< 0.001	179	3.8	153	6.4	< 0.001
Pain	1060	8.1	237	9.8	0.004	365	7.7	237	9.8	0.003

SLNB sentinel lymph node biopsy