Table 3.

Univariate and multivariate Cox regression analyses of patient, tumor, and treatment characteristics with recurrence.

	Univariate analysis		Multivariate analysis
	HR (95% CI)	p-value	HR (95% CI)	p-value
Age (10-year intervals)	1.09 (0.80–1.48)	0.58	—	—
Sex
Male	1.20 (0.45–3.18)	0.72	—	—
Female	Ref
Tumor location
Upper extremity	5.71 (1.46–22.34)	0.03	—	—
Lower extremity	Ref
Tumor size (5-cm intervals)	0.85 (0.57–1.28)	0.43	—	—
MDM2 status
Positive	Ref
Unavailable	0.28 (0.10–0.81)	0.01	—	—
Tumor depth
Deep	Ref
Superficial	0	0.35	—	—
Tumor NVI
Yes	2.35 (0.89–6.25)	0.08	—	—
No	Ref
Surgical resection margins
R0/R1	Ref
R2	9.88 (2.02–48.38)	0.02	11.04 (2.07–59.03)	<0.001
Treatment center
Center 1	Ref
Center 2	4.56 (1.64–12.65)	0.003	—	—
Radiation
Yes	Ref
No	23.22 (3.05– 176.94)	<0.001	23.63 (3.09–180.48)	<0.001

HR, hazard ratio; CI, confidence interval; ref, reference group; NVI, neurovascular involvement.