Table 3.

Prognostic factors for overall survival in cohort 2 with surgery (metachronous metastatic disease): univariate and multivariate analyses (n = 322)

Characteristics	Univariate analysis				Multivariate analysis
	Hazard ratio	95% CI		P> |z|	Hazard ratio	95% CI		P> |z|
Age at metastatic diagnosis (continuous variable)	1.01	0.99	1.01	0.62	1.01	0.99	1.01	0.12
Age ≤25 years versus >25 years old	1.11	0.78	1.58	0.55
Sex (male versus female)	1.16	0.90	1.49	0.24
Year of metastasis diagnosis:
2000-2010 versus <2000	0.80	0.60	1.06	0.12
>2010 versus <2000	0.82	0.59	1.14	0.23
Tumor size of primary tumor <50 mm or >50 mm	1.08	0.78	1.50	0.63
Surgery in network versus extra network	0.67	0.52	0.88	<0.01	0.57	0.41	0.78	<0.01
Margin of primary tumor (n = 219)a
R1 versus R0	1.28	0.92	1.76	0.14
R2 versus R0	1.69	0.98	2.92	0.06
Radiotherapy in perioperative setting versus no	0.81	0.20	3.34	0.77
Chemotherapy in perioperative setting versus no	1.26	0.98	1.63	0.07	1.56	1.08	2.26	0.02
Metastatic site:
Other single versus lung single	1.58	1.13	2.22	<0.01	1.67	1.16	2.41	<0.01
Multiple versus lung single	3.44	2.18	5.43	<0.01	2.17	1.32	3.57	<0.01
Time to first metastasis >12 months versus <12 months	0.45	0.34	0.60	<0.01	0.36	0.25	0.52	<0.01
Local treatment at first metastatic line	0.34	0.25	0.45	<0.01	0.40	0.29	0.57	<0.01
Ifosfamide at first metastatic line versus no (n = 236)	0.64	0.48	0.84	<0.01	0.69	0.51	0.93	0.02
Doxorubicin at first metastatic line versus no (n = 236)	0.68	0.52	0.90	0.006	0.75	0.52	1.08	0.12

Characteristics that are clinically significant are highlighted in bold.

Only age at metastatic diagnosis and variables that had a P value of significance <0.10 in the univariate analysis were introduced in the semi-parametric multivariate Cox model.

CI, confidence interval.

^aMargin of primary tumor was not introduced in multivariate analysis due to missing data.