Table 2 Independent prognostic factors associated with time to death at multivariate analysis using cox proportional hazards model

Age

0.000

 <60

Ref

-

 ≥60

1.760

1.489–2.079

ECOG PS

0.001

 0–1

Ref

-

 2–5

1.968

1.317–2.940

Tumor size

0.014

 <5 cm

Ref

 ≥5 cm

1.267

1.050–1.529

Depth

0.000

 T1

Ref

-

 T2

1.499

1.097–2.050

 T3

2.160

1.640–2.845

 T4a

3.153

2.338–4.253

 T4b

4.910

2.504–9.628

Nodal status

0.000

 N0

Ref

-

 N1

1.151

0.820–1.616

 N2

1.379

0.979–1.942

 N3

2.863

2.062–3.976

TNM Stage

0.000

 I

Ref

-

 II

2.328

1.752–3.093

 III

3.387

2.235–5.133