Table 1.
Sociodemographic and clinical characteristics of the participants.
| No. of patients (%) | |||
|---|---|---|---|
| Variables | Training cohort n = 733 (100%) | Validation cohort n = 424 (100%) | P-value |
| Age groups | |||
| <45 | 368 (50.2) | 174 (41.0) | 0.003 |
| ≥45 | 365 (49.8) | 250 (59.0) | |
| Sex | |||
| Male | 534 (72.9) | 320 (75.5) | 0.329 |
| Female | 199 (27.2) | 104 (24.5) | |
| WHO histologic types | |||
| I | 5 (0.7) | 0 (0.0) | <0.010 |
| II | 39 (5.3) | 0 (0.0) | |
| III | 689 (94.0) | 424 (100.0) | |
| EBV level copies/ml | |||
| <4,000 | 421 (57.4) | 395 (93.2) | <0.010 |
| ≥4,000 | 312 (42.6) | 29 (6.8) | |
| T-stage* | |||
| T1 | 184 (25.1) | 117 (27.6) | 0.042 |
| T2 | 87 (11.9) | 57 (13.4) | |
| T3 | 282 (38.5) | 128 (30.2) | |
| T4 | 180 (24.6) | 122 (28.8) | |
| N-stage* | |||
| N0 | 174 (23.7) | 73 (17.2) | 0.022 |
| N1 | 398 (54.3) | 236 (55.7) | |
| N2 | 105 (14.3) | 82 (19.3) | |
| N3 | 56 (7.6) | 33 (7.8) | |
| AJCC stage* | |||
| I | 68 (9.3) | 36 (8.5) | 0.810 |
| II | 157 (21.4) | 98 (23.1) | |
| III | 285 (38.9) | 156 (36.8) | |
| IV | 223 (30.4) | 134 (31.6) | |
| Induction chemotherapy | |||
| No | 379 (51.7) | 197 (46.5) | 0.086 |
| Yes | 354 (48.3) | 227 (53.5) | |
| Chemotherapy | |||
| No | 99 (13.5) | 69 (16.3) | 0.198 |
| Yes | 634 (86.5) | 355 (83.7) | |
| Laterality of RLN metastasis | |||
| No/unilaterality | 540 (73.7) | 279 (68.2) | 0.050 |
| Bilaterality | 193 (26.3) | 130 (31.8) | |
| Cervical lymph nodes metastasis | 598 (81.6) | 324 (76.4) | 0.035 |
| No/unilaterality | |||
| Bilaterality | 135 (18.4) | 100 (23.6) | |
| Regions | |||
| No | 174 (23.7) | 73 (17.2) | 0.033 |
| Upper region | 505 (68.9) | 318 (75.0) | |
| Lower region | 54 (7.4) | 33 (7.8) | |
| Nodal size | |||
| <6 cm | 729 (99.4) | 410 (96.7) | <0.010 |
| ≥6 cm | 4 (0.6) | 14 (3.3) | |
| Nodal grouping | |||
| No | 560 (76.4) | 340 (80.2) | 0.135 |
| Yes | 173 (23.6) | 84 (19.8) | |
| Central nodal necrosis | |||
| No/unilaterality | 692 (94.4) | 336 (79.3) | <0.010 |
| Bilaterality | 41 (5.6) | 88 (20.8) | |
| Extracapsular spread | |||
| No | 653 (89.1) | 384 (90.6) | 0.426 |
| Yes | 80 (10.9) | 40 (9.4) | |
EBV, Epstein–Barr virus; AJCC, American Joint Committee on Cancer; RLN, retropharyngeal lymph node.
*
8th version of the TNM staging system.