Table 3. Associations between patient-, tumor-, and therapy-related characteristics and OS.
| Parameter | No. | PFS | OS | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Univariate analysis | Multivariate analysis | Univariate analysis | Multivariate analysis | |||||||||
| HR (95% CI) | P | HR (95% CI) | Pa | HR (95% CI) | P | HR (95% CI) | Pa | |||||
| Sex | ||||||||||||
| Male | 138 | 1.000 | – | 1.000 | – | 1.000 | – | 1.000 | – | |||
| Female | 49 | 0.651 (0.434–0.977) | 0.038 | 0.751 (0.482–1.169) | 0.205 | 0.646 (0.428–0.975) | 0.037 | 0.817 (0.522–1.279) | 0.376 | |||
| Age, years | ||||||||||||
| ≤65 | 112 | 1.000 | – | 1.000 | – | 1.000 | – | 1.000 | – | |||
| >65 | 75 | 1.153 (0.822–1.617) | 0.409 | 1.240 (0.862–1.783) | 0.246 | 1.192 (0.846–1.678) | 0.315 | 1.319 (0.913–1.904) | 0.140 | |||
| No. of pack yearsb | ||||||||||||
| ≤18 | 112 | 1.000 | – | 1.000 | – | 1.000 | – | 1.000 | – | |||
| >18 | 70 | 1.228 (0.869–1.734) | 0.244 | 0.936 (0.644–1.360) | 0.729 | 1.291 (0.911–1.832) | 0.152 | 0.982 (0.675–1.429) | 0.924 | |||
| Chemotherapy | ||||||||||||
| No | 49 | 1.000 | – | 1.000 | – | 1.000 | – | 1.000 | – | |||
| Yes | 138 | 0.903 (0.621-1.311) | 0.591 | 0.729 (0.468–1.135) | 0.162 | 0.861 (0.594–1.276) | 0.479 | 0.684 (0.436–1.073) | 0.098 | |||
| Fraction dose, Gy | ||||||||||||
| ≤2 | 141 | 1.000 | – | 1.000 | – | 1.000 | – | 1.000 | – | |||
| >2 | 46 | 0.547(0.361-0.831) | 0.005 | 0.532 (0.325-0.870) | 0.012 | 0.522 (0.337-0.810) | 0.004 | 0.485 (0.291-0.809) | 0.006 | |||
| Stagec | ||||||||||||
| I–II | 67 | 1.000 | – | – | – | 1.000 | – | – | – | |||
| III–IV | 120 | 2.076 (1.432–3.008) | 0.000 | – | – | 2.094 (1.434-3.059) | 0.000 | – | – | |||
| Radiation dose, Gy | ||||||||||||
| ≤61.2 | 87 | 1.000 | – | 1.000 | – | 1.000 | – | 1.000 | – | |||
| >61.2 | 100 | 0.695 (0.497–0.973) | 0.034 | 0.777 (0.497–1.216) | 0.270 | 0.713 (0.506–1.005) | 0.053 | 0.830 (0.531–1.298) | 0.414 | |||
| LGTV-P, cm | ||||||||||||
| ≤7 | 133 | 1.000 | – | 1.000 | – | 1.000 | – | 1.000 | – | |||
| >7 | 52 | 1.491 (1.036–2.147) | 0.032 | 0.968 (0.635–1.477) | 0.881 | 1.669 (1.159–2.404) | 0.006 | 1.080 (0.706–1.652) | 0.723 | |||
| GTV, cm3 | ||||||||||||
| ≤39.41 | 93 | 1.000 | – | 1.000 | – | 1.000 | – | 1.000 | – | |||
| >39.41 | 92 | 2.508 (1.768–3.557) | 0.000 | 2.865 (1.897–4.326) | 0.000 | 2.796 (1.961–3.988) | 0.000 | 3.152 (2.066–4.807) | 0.000 | |||
| GTV-P, cm3 | ||||||||||||
| ≤32.17 | 102 | 1.000 | – | – | – | 1.000 | – | – | – | |||
| >32.17 | 83 | 2.332 (1.655–3.287) | 0.000 | – | – | 2.839 (2.003–4.023) | 0.000 | – | – | |||
| GTV-N, cm3 | ||||||||||||
| ≤4.47 | 95 | 1.000 | – | – | – | 1.000 | – | – | – | |||
| >4.47 | 90 | 1.852 (1.316–2.606) | 0.000 | – | – | 1.851 (1.307–2.621) | 0.001 | – | – | |||
a, P values were calculated with adjustment for age, sex, smoking status, chemotherapy history, fraction dose, radiation dose, LGTV-P and GTV; b, smoking status of 5 patients were missing; c, UICC 6th edition. OS, overall survival; PFS, progression-free survival; HR, hazards ratio; CI, confidence interval; LGTV-P, length of gross tumor volume of primary esophageal cancer; GTV, gross tumor volume; GTV-P, gross tumor volume of primary esophageal cancer; GTV-N, gross tumor volume of metastases lymph nodes.