Table 6.
Prognostic factor analyses using Cox’s regression method with backward selection for progression-free survival and overall survival
| Variable | Progression-free survival |
Overall survival |
||||||
|---|---|---|---|---|---|---|---|---|
| Univariate analysis |
Multivariate analysis |
Univariate analysis |
Multivariate analysis |
|||||
| HR (95% Cl) | p-value | HR (95% Cl) | p-value | HR (95% Cl) | p-value | HR (95% Cl) | p-value | |
| Age (< 50 yr vs. ≥ 50 yr) | 0.67 (0.33-1.37) | 0.28 | - | - | 0.44 (0.17-1.18) | 0.1 | - | - |
| Sex (female vs. male) | 0.91 (0.42-1.98) | 0.81 | - | - | 1.46 (0.56-3.76) | 0.44 | - | - |
| ECOG performance (0 vs. 1) | 0.34 (0.15-0.74) | 0.007 | 0.4 (0.16-1.02) | 0.06 | 0.32 (0.12-0.89) | 0.03 | - | - |
| WHO classification (NK vs. others) | 1.04 (0.25-4.36) | 0.96 | - | - | 0.62 (1.4-2.69) | 0.52 | - | - |
| T stage (Tl-2 vs. T3-4) | 1.77 (0.85-3.69) | 0.13 | - | - | 0.27 (0.09-0.84) | 0.02 | 0.29 (0.09-0.9) | 0.03 |
| N stage (NO vs. Nl-3) | 2.32 (0.31-17.1) | 0.41 | - | - | 1.01 (0.13-7.77) | 0.99 | - | - |
| TNM staging (III vs. IVa-b) | 0.32 (0.15-0.65) | 0.002 | 0.36 (0.16-0.8) | 0.01 | 0.33 (0.13-0.85) | 0.02 | - | - |
| Radiotherapy modality (IMRT vs. 3D-CRT) | 0.68 (0.32-1.44) | 0.31 | - | - | 0.37 (0.15-0.94) | 0.04 | 0.36 (0.14-0.92) | 0.03 |
| EQD2 (α/β ratio=10) (≥ 70 Gy vs.< 70 Gy) | 0.68 (0.33-1.41) | 0.3 | - | - | 0.46 (0.18-1.15) | 0.1 | - | - |
| Chemotherapy (concurrent vs. induction vs. none) | Reference | 0.23 | Reference | 0.01 | Reference | 0.28 | - | - |
| 0.88 (0.26-2.98) | 0.18 (0.04-0.82) | 1.05 (0.23-4.72) | - | |||||
| 0.45 (0.12-1.69) | 0.08 (0.02-0.41) | 0.42 (0.08-2.34) | - | |||||
| TLG (low vs. high) | 0.3 (0.15-0.61) | 0.001 | 0.3 (0.14-0.65) | 0.002 | 0.27 (0.1-0.69) | 0.006 | 0.29 (0.11-0.79) | 0.02 |
| Whole tumor volume (continuous) (mL) | 1.01 (1.003-1.02) | 0.005 | - | - | 1.01 (1-1.02) | 0.16 | - | - |
HR, hazard ratio; CI, confidence interval; ECOG, Eastern Cooperative Oncology Group; WHO, World Health Organization; TNM, tumor-node-metastasis; IMRT, intensity-modulated radiation therapy; 3D-CRT, 3-Dimensional conformal radiation therapy; EQD2, equivalent dose in 2 Gy fractions; TLG, total lesion glycolysis for whole tumor.