Table 4 Cox proportional hazards analysis for overall survival

Adjuvant treatment (no/yes)

0.407

0.207–1.020

0.056

R 1 (negative/positive)

1.260–15.468

0.020

Extended resection (no/yes)

1.105–5.945

0.028

Operation (LDP/ODP)

0.420–1.863

0.885

N1 (negative/positive)

0.745–4.147

0.198

Perineural invasion (negative/positive)

1.240–6.746

0.014

Tumor stage T2

1.000

Tumor stage T3

0.776

0.292–2.060

0.611

Tumor stage T4

1.174

0.433–3.180

0.753

Tumor differentitation Well

1.000

Tumor differentitation Moderate

3.432

1.012–11.645

0.048

Tumor differentitation Poor

6.316

0.980–40.700

0.053