Table 2 Prognostic factors for OS according to univariable Cox model

Age (years)

 <60

1 (ref)

 60–68

1.01 (0.82–1.25)

0.89

 69–77

1.30 (1.06–1.59)

0.011

 > 78

2.09 (1.67–2.61)

< 0.001

Local tumor stage

 T1–3

1 (ref)

 T4

1.46 (1.19–1.79)

< 0.001

ECOG

 0

1 (ref)

 1

1.41 (1.06–1.88)

0.018

 2

2.94 (2.18–3.98)

< 0.001

Number of metastatic sites

 1

1 (ref)

 2

1.37 (1.13–1.67)

0.001

 ≥ 3

1.79 (1.49–2.16)

< 0.001

Local lymph node metastases

1.29 (1.10–1.50)

0.001

Distant lymph node metastases

1.19 (1.01–1.41)

0.041

Bone metastases

1.21 (1.03–1.43)

0.021

Liver metastases

1.52 (1.25–1.84)

< 0.001

Brain metastases

1.84 (1.28–2.63)

0.001

 Adrenal metastases

1.06 (0.88–1.29)

0.525

 Lung metastases

1.10 (0.94–1.29)

0.225

Histology

 Clear cell carcinoma

1 (ref)

 Other

1.54 (1.18–2.00)

0.001

 Not available

2.63 (2.20–3.14)

< 0.001

CRP > ULN

1.44 (1.14–1.82)

0.002

Hemoglobin < LLN

1.50 (1.25–1.80)

< 0.001