Table 2.

Multivariable Cox proportional hazards analyses of overall survival

Characteristics	Dedifferentiated chondrosarcoma (n = 185) HR (95% CI)	p value	Osteosarcoma (n = 2261) HR (95% CI)	p value
Sex		0.19		0.002
Male	Referent		Referent
Female	0.78 (0.53-1.13)		0.79 (0.68-0.92)
Age in years		0.09		< 0.001
0-66	Referent
> 66	1.40 (0.95-2.06)
0-17			Referent
< 17			1.58 (1.35-1.85)
Tumor size
≤ 8 cm	Referent		Referent
> 8 cm	1.26 (0.84-1.88)	0.26	1.22 (1.03-1.45)	0.02
Missing	1.82 (1.08-3.07)	0.03	1.15 (0.93-1.42)	0.19
SEER stage		0.57		< 0.001
Local	Referent		Referent
Regional	1.12 (0.76-1.64)		1.64 (1.40-1.93)
Tumor grade
Low (I and II)	0.86 (0.46-1.58)	0.62	0.36 (0.24-0.55)	< 0.001
High (III and IV)	Referent		Referent
Missing	1.22 (0.73-2.03)	0.44	0.96 (0.79-1.15)	0.64
Primary tumor location		0.06		< 0.001
Extremities	Referent		Referent
Trunk or bone, NOS	0.66 (0.43-1.01)		1.97 (1.59-2.43)
Radiation		0.54		< 0.001
No/unknown	Referent		Referent
Yes	1.15 (0.74-1.79)		1.85 (1.41-2.42)
Chemotherapy		0.16		0.002
No/unknown	Referent		Referent
Yes	0.75 (0.49-1.12)		0.69 (0.55-0.88)

NOS = not otherwise specified.