Prognostic Factors and Treatment Results of High-Grade Osteosarcoma in Norway: A Scope Beyond the “Classical” Patient

Table 5

Multivariate Cox-regression analysis of prognostic factors and treatment-related variables for overall survival and event-free survival. All high-grade osteosarcomas.

Variables^a	Overall survival		Event-free survival
	RR^b		RR^b
	(95% CI^c)		(95% CI^c)
Adequate primary treatment
Yes	1		1
No	3.6 (2.3–5.4)	<0.001	6.6 (3.9–11.1)	<0.001
Uncertain	5.0 (1.2–21.8)	0.031	5.5 (1.3–23.5)	0.022
Elevated LDH	1.5 (1.1–2.1)	0.015	1.7 (1.2–2.4)	0.002
Primary metastatic disease	2.3 (1.5–3.4)	<0.001
Year of diagnosis
1975–1979	1.5 (0.8–2.8)	0.195	0.7 (0.4–1.4)	0.315
1980–1989	2.1 (1.3–3.2)	0.002	2.0 (1.2–3.2)	0.005
1990–1999	1.7 (1.1–2.7)	0.023	1.7 (1.0–2.8)	0.048
2000–2009	1		1
Age >40 years	1.5 (1.0–2.2)	0.041	1.0 (0.6–1.5)	0.930
Tumour size >10 cm	1.4 (1.0–2.0)	0.046
Axial primary tumour	1.4 (0.9–2.2)	0.124	1.1 (0.7–1.8)	0.587

Reference values in line with Table 4. ^bRelative risk, ^cconfidence interval, and value.