Table 3 Univariate analysis for patient’s characteristics and treatment factors

Age

<83

1

0.495

1

0.438

≥83

1.333

0.334–11.875

2.098

0.776–18.226

Sex

Male

1

0.534

1

0.402

Female

1.785

0.287–11.128

2.561

0.284–23.047

ECOG-PS

0

1

0.091

1

0.026*

≥1

5.250

0.766–35.978

9.265

1.331–44.532

T classification

2 or 3

1

0.149

1

0.066

≥4a

2.258

0.745–6.839

4.084

0.911–18.303

N classification

0 or1

1

0.632

1

0.435

≥2b

1.240

0.513–2.996

2.223

0.298–16.559

Stage

II, III

1

0.237

1

0.083

≥IVA

2.075

0.618–6.968

7.147

0.776–56.792

Total dose of RT^d

≥60 Gy

1

0.208

1

0.435

<60 Gy

0.233

0.024–2.252

1.575

0.987–25.154

Treatment delay^a

No

1

0.264

1

0.044*

Yes

2.667

0.477–14.904

7.965

1.052–45.271