Table 2.
Clinical model parameters and c-index model performance.
| Overall survival (OS) | ||||
|---|---|---|---|---|
| Variables | Category | Coefficients | Hazard ratio | p value |
| Performance score | 0 | 0 | 1 | ref |
| 1 | 0.469 | 1.6 (1.28–1.99) | <0.0001 | |
| ≥2 | 0.781 | 2.18 (1.51–3.16) | 0.0001 | |
| AJCC8th stage | I | 0 | 1 | ref |
| II | 0.117 | 1.12 (0.76–1.65) | 0.5545 | |
| III | 0.679 | 1.97 (1.42–2.74) | 0.0001 | |
| IVa | 0.793 | 2.21 (1.66–2.94) | <0.0001 | |
| IVb | 1.509 | 4.52 (2.79–7.33) | <0.0001 | |
| Pack years | ≤5 | 0 | 1 | ref |
| 5–25 | 0.267 | 1.31 (1.01–1.7) | 0.0459 | |
| 26–50 | 0.499 | 1.65 (1.3–2.08) | <0.0001 | |
| >50 | 0.867 | 2.38 (1.78–3.17) | <0.0001 | |
| Age | ≤55 | 0 | 1 | ref |
| 56–65 | 0.085 | 1.09 (0.89–1.33) | 0.4113 | |
| 65–75 | 0.400 | 1.49 (1.2–1.85) | 0.0003 | |
| >75 | 0.753 | 2.12 (1.56–2.89) | <0.0001 | |
| Local control (LC) | ||||
| Variables | Category | Coefficients | Hazard ratio | p value |
|
| ||||
| T stage | T1 | 0 | 1 | ref |
| T2 | 1.432 | 4.19 (2.19–8.03) | <0.0001 | |
| T3 | 1.473 | 4.36 (2.22–8.58) | <0.0001 | |
| T4 | 1.613 | 5.02 (2.56–9.83) | <0.0001 | |
| HPV status | positive = 1 | −0.694 | 0.5 (0.34–0.73) | 0.0003 |
| Performance score | 0 | 0 | 1 | ref |
| 1 | 0.421 | 1.52 (1.05–2.22) | 0.0276 | |
| ≥2 | 0.801 | 2.23 (1.38–3.59) | 0.0010 | |
| Pack years | ≤5 | 0 | 1 | ref |
| 5–25 | −0.039 | 0.96 (0.58–1.6) | 0.8807 | |
| 26–50 | 0.294 | 1.34 (0.87–2.08) | 0.1858 | |
| >50 | 0.496 | 1.64 (1.02–2.64) | 0.0403 | |
| Regional control (RC) | ||||
| Variables | Category | Coefficients | Hazard ratio | p value |
|
| ||||
| AJCC8th stage | I | 0 | 1 | ref |
| II | 0.442 | 1.56 (0.7–3.46) | 0.2774 | |
| III | 0.984 | 2.68 (1.28–5.59) | 0.0089 | |
| IVa | 1.567 | 4.79 (2.34–9.81) | <0.0001 | |
| IVb | 2.565 | 13 (4.76–35.55) | <0.0001 | |
| Performance score | 0 | 0 | 1 | ref |
| 1 | 0.573 | 1.77 (1.15–2.73) | 0.0093 | |
| ≥2 | 0.793 | 2.21 (1.27–3.84) | 0.0049 | |
| Tumour site | Hypopharynx | 0 | 1 | ref |
| Larynx | −0.118 | 0.89 (0.45–1.75) | 0.7343 | |
| Oropharynx | −0.648 | 0.52 (0.25–1.11) | 0.0898 | |
| Oral cavity | −0.853 | 0.43 (0.21–0.88) | 0.0203 | |
| Unknown Prim | −1.140 | 0.32 (0.07–1.51) | 0.1493 | |
| Nasopharynx | −4.995 | 0.01 (0–21498.48) | 0.9932 | |
| Model performance (c-index [95%CI]) | ||||
| MDACC Training | MDACC validation | UMCG external validation 1 | MGH external validation 2 | |
|
| ||||
| Overall Survival (OS) | 0.72 [0.66–0.78] | 0.76 [0.68–0.83] | 0.73 [0.68–0.78] | 0.75 [0.69–0.81] |
| Local control (LC) | 0.74 [0.67–0.82] | 0.71 [0.58–0.84] | 0.70 [0.62–0.77] | 0.75 [0.61–0.90] |
| Regional control (RC) | 0.74 [0.64–0.83] | 0.73 [0.57–0.89] | 0.7 [0.62–0.78] | 0.74 [0.56–0.91] |
Abbreviations: HPV, human papilloma virus; CI, confidence interval.