Table 1.

Categorical variables contained in the training and validation sets

Feature	Training set (n = 189)		Validation set (n = 815)			p Value
	Number of patients	Percent	Number of patients	Percent	Percent missing
Gender
Male	85	45	369	45	0	0.91
Female	104	55	446	55
Diagnosis group
1.0	52	27	173	21	< 1	< 0.001*
2.0	34	18	74	9
3.0	103	55	567	70
Visceral metastases
Yes	114	60	325	40	6	< 0.001*
No	75	40	441	54
Lymph node metastases
Yes	36	19	169	21	62	< 0.001*
No	153	81	143	18
Number of bone metastases
Solitary	55	29	123	15	3	< 0.001*
Multiple	134	71	666	82
Pathologic fracture
Complete	84	44	614	75	< 1	< 0.001*
Impending	105	56	196	24
ECOG performance status
0, 1, or 2	93	49	558	68	0	< 0.001*
3 or 4	96	51	257	32
Survival > 1 months
Yes	173	92	622	87	0	< 0.001*
No	16	8	193	13
Survival > 6 months
Yes	111	59	372	46	0	0.001*
No	78	41	443	54

*Distributions are significantly different between the training and validation sets by the chi square method; Percent missing = the proportion of unknown or missing data in the validation set; ECOG = Eastern Cooperative Oncology Group.