Table 4 Multivariate analyses of risk factors regarding 5-year overall and disease-free survivals using Cox regression model among different quality of neck dissection, a sensitivity test (85%), n = 1605

0.61 (0.45–0.81)

0.001

0.70 (0.45–1.11)

0.128

0.99 (0.76–1.28)

0.931

0.88 (0.66–1.18)

0.397

1.14 (0.69–1.87)

0.606

1.06 (0.81–1.39)

0.672

1.04 (1.03–1.05)

 < 0.001

1.04 (1.02–1.06)

0.001

1.01 (1.001–1.02)

0.038

1.70 (1.28–2.25)

 < 0.001

1.88 (1.17–3.03)

0.009

1.69 (1.30–2.20)

 < 0.001

1.10 (0.79–1.54)

0.562

1.27 (0.77–2.10)

0.357

1.20 (0.90–1.61)

0.209

0.48 (0.33–0.69)

 < 0.001

0.52 (0.29–0.93)

0.028

0.33 (0.23–0.47)

 < 0.001

0.62 (0.41–0.93)

0.020

1.06 (0.57–1.99)

0.848

1.20 (0.86–1.67)

0.297

0.76 (0.51–1.13)

0.169

1.12 (0.58–2.19)

0.732

0.97 (0.70–1.36)

0.868

1.02 (1.01–1.04)

0.011

1.03 (0.99–1.06)

0.054

1.00 (0.98–1.01)

0.696

1.65 (1.11–2.46)

0.013

2.01 (1.04–3.91)

0.039

1.49 (1.07–2.08)

0.017

1.24 (0.79–1.96)

0.353

1.71 (0.87–3.35)

0.119

1.38 (0.97–1.98)

0.077

0.37 (0.21–0.63)

 < 0.001

0.17 (0.06–0.48)

0.001

0.29 (0.19–0.46)

 < 0.001