Table 5 Cox univariate and multivariate analyses of the prognostic factors related to overall survival (OS) for the patients with postradiation nasopharyngeal necrosis
Clinical characteristic | 2-year OS rate (%) | Univariate analysis | Multivariate analysis | ||
|---|---|---|---|---|---|
P value | HR (95% CI) | P value | HR (95% CI) | ||
Gender |  | 0.601 | 1.295 (0.491–3.412) |  |  |
 Female | 84.0 |  |  |  |  |
 Male | 76.0 |  |  |  |  |
Age (years) |  | 0.331 | 1.589 (0.625–4.039) |  |  |
 < 51 | 84.7 |  |  |  |  |
 ≥ 51 | 72.7 |  |  |  |  |
Cycles of radiotherapy |  | 0.717 | 1.197 (0.453–3.163) |  |  |
 One | 80.8 |  |  |  |  |
 Two | 71.9 |  |  |  |  |
Necrosis-free interval |  | 0.617 | 1.372 (0.397–4.737) |  |  |
 Acute necrosis | 86.3 |  |  |  |  |
 Chronic necrosis | 75.7 |  |  |  |  |
Carotid artery exposure |  | 0.817 | 1.122 (0.423–2.975) |  |  |
 Yes | 68.6 |  |  |  |  |
 No | 82.1 |  |  |  |  |
Osteoradionecrosis |  | 0.607 | 0.782 (0.308–1.991) |  |  |
 Yes | 81.2 |  |  |  |  |
 No | 71.4 |  |  |  |  |
Postoperative pathological result |  | 0.001 | 5.026 (1.974–12.799) | 0.001 | 5.018 (1.970–12.782) |
 Negative | 88.4 |  |  |  |  |
 Positive | 54.2 |  |  |  |  |
Status of the flap |  | 0.055 | 2.467 (0.982–6.195) | 0.056 | 2.442 (0.978–6.099) |
 Survived | 80.3 |  |  |  |  |
 Necrotized | 68.8 |  |  |  |  |