Table 3.

Multivariate Cox regression analyses for localized melanoma by dataset

		Chi-square values (Wald)
Variable*	Degree of Freedom (DF)	Model Development (Training) Dataset (n=14,760) %	Model Validation (Testing) Dataset (n=10,974) %
Tumor Thickness	5	232.9	229.4
Ulceration	1	126.2	95.0
Age	4	91.9	27.9
Lesion Site	1	45.5	41.0
Gender	1	23.9	19.8
Level of Invasion	3	21.2	5.5

^*Variable coding in the Cox regression model: Tumor thickness (1=0–0.50mm; 2=0.51–1.00mm; 3=1.01–2.00mm; 4= 2.01–3.00mm; 5=3.00–6.00mm; 6=>6.00mm); Ulceration (0=no; 1=yes); Age (1=<50; 2=50–59; 3=60–69; 4=70–79; 5=≥80); Lesion site (0=extremity; 1=axial); Gender (0=female; 1=male); and Level of invasion (1=level II; 2=level III; 3=level IV; 4=level V)