Table 5 Univariate and multivariate analyses of risk factors on PFS for locoregional recurrence and distant metastasis

Age (> 60 vs. ≤60)

1.25 (0.74–2.13)

0.408

0.88 (0.46–1.68)

0.695

Sex (Male vs. Female)

0.16 (0.04–0.57)

0.005

0.13 (0.04–0.50)

0.003

1.26 (0.44–3.36)

0.670

Smoking (Former/current vs. Never)

0.86 (0.36–2.04)

0.735

1.09 (0.51–2.32)

0.819

Betel nuts (Former/current vs. Never)

0.85 (0.49–1.47)

0.562

0.88 (0.46–1.70)

0.709

Performance status scale (ECOG ≧1 vs. 0)

1.56 (0.91–2.66)

0.105

0.92 (0.42–2.02)

0.827

Primary tumor location (Oral cavity vs. Others)

0.87 (0.51–1.50)

0.615

1.13 (0.57–2.23)

0.732

Primary tumor location (Hypolarynx/ larynx vs. others)

1.36 (0.73–2.53)

0.330

1.34 (0.68–2.62)

0.399

 Neoadjuvant chemotherapy (Yes vs. No)

1.03 (0.60–1.75)

0.917

1.05 (0.49–2.23)

0.906

 Primary CCRT (Yes vs. No)

0.85 (0.50–1.45)

0.554

1.00 (0.51–1.96)

0.994

 Adjuvant CCRT (Yes vs. No)

0.88 (0.51–1.52)

0.638

1.09 (0.57–2.10)

0.798

Recurrence after RT (<  6 months vs. >  6 months)

1.30 (0.76–2.22)

0.347

3.14 (1.43–6.89)

0.004

 Salvage surgery (Yes vs. No)

0.36 (0.16–0.81)

0.014

0.30 (0.13–0.69)

0.005

 Salvage radiotherapy (Yes vs. No)

1.07 (0.54–2.12)

0.849