Table II. Primary tumor characteristics.

	Patients with BM	Patients without BM	P value* (univariate)	P value # (multivariate)
Primary tumor location			0.014, global
Head & Neck	36 (29.27%)	57 (24.05%)	0.31
Scalp	17 (13.82%)	15 (6.33%)	0.030	0.11
Face	16 (13.00%)	29 (12.24%)	0.87
Neck	3 (2.44%)	13 (5.49%)	0.28
Trunk	46 (37.40%)	75 (31.65%)	0.29
Chest & Back	45 (36.56%)	74 (31.22%)	0.34
Axilla	1 (0.81%)	1 (0.42%)	1.00
Extremity	37 (30.08%)	103 (43.46%)	0.017
Arm	22 (17.89%)	45 (18.99%)	0.89
Leg	15 (12.20%)	58 (24.47%)	0.006	0.017
Other	4 (3.25%)	2 (0.84%)	0.19
Genital	2 (1.63%)	2 (0.84%)	0.61
Unknown primary	2 (1.63%)	0 (0.00%)	0.12
Histologic type+			0.11, global
SSM	35 (40.70%)	94 (51.09%)	0.12
NM	33 (38.37%)	44 (23.91%)	0.020	0.56
LMM	9 (10.47%)	27 (14.67%)	0.44
Other	9 (10.47%)	19 (10.33%)	1.00
Breslow depth╪			0.11, trend	0.058, trend
<1.00 mm	27 (23.68%)	78 (34.51%)	0.046
1.00-1.99 mm	32 (28.07%)	65 (28.76%)	1.00
2.00-3.99 mm	24 (21.05%)	43 (19.03%)	0.67
>4.00 mm	31 (27.19%)	40 (17.70%)	0.048
Ulceration╫
Absent	66 (59.46%)	133 (66.17%)	0.27
Present	45 (40.54%)	68 (33.83%)	0.27
Mutation testing‖
BRAF	20 (48.78%)	7 (50.00%)	1.00
NRAS	7 (17.07%)	1 (7.14%)	0.66
C-kit	3 (7.32%)	0 (0.00%)	0.56
No mutation detected	11 (26.83%)	6 (42.86%)	0.32

BM, brain metastasis.

^*Fisher's Exact test

^#Logistic regression model

⁺Histologic type was unknown in 37 patients with BM and 53 patients without BM.

^╪Breslow depth was unknown in 9 patients with BM and 11 patients without BM.

^╫Ulceration was unknown in 12 patients with BM and 36 patients without BM.

^‖Mutation testing not done (or results unknown) 82 patients with BM and 223 patients without BM.