Clinical characteristics of patients in the training and external validation cohorts
| Training cohort (N=194) | Validation cohort (N=304) | |||||
| Patients (n) | Low-risk | High-risk | Patients (n) | Low-risk | High-risk | |
| Age (years) | ||||||
| <45 | 100 (51.5) | 74 (74.0) | 26 (26.0) | 121 (39.8) | 93 (76.9) | 28 (23.1) |
| ≥45 | 94 (48.5) | 78 (83.0) | 16 (17.0) | 183 (60.2) | 141 (77.0) | 42 (23.0) |
| Sex | ||||||
| Male | 133 (68.6) | 102 (76.7) | 31 (23.3) | 215 (70.7) | 163 (75.8) | 52 (24.2) |
| Female | 61 (31.4) | 50 (82.0) | 11 (18.0) | 89 (29.3) | 71 (79.8) | 18 (20.2) |
| Pathological type | ||||||
| WHO II | 4 (2.1) | 3 (75.0) | 1 (25.0) | 9 (3.0) | 8 (88.9) | 1 (11.1) |
| WHO III | 190 (97.9) | 149 (78.4) | 41 (21.6) | 295 (97.0) | 226 (76.6) | 69 (23.4) |
| T stage* | ||||||
| T1 | 9 (4.6) | 6 (66.7) | 3 (33.3) | 28 (9.2) | 24 (85.7) | 4 (14.3) |
| T2 | 34 (17.5) | 25 (73.5) | 9 (26.5) | 111 (36.5) | 88 (79.3) | 23 (20.7) |
| T3 | 109 (56.2) | 88 (80.7) | 21 (19.3) | 98 (32.2) | 71 (72.4) | 27 (27.6) |
| T4 | 42 (21.6) | 33 (78.6) | 9 (21.4) | 67 (22.0) | 51 (76.1) | 16 (23.9) |
| N stage* | ||||||
| N0 | 9 (4.6) | 9 (100.0) | 0 (0.0) | 27 (8.9) | 22 (81.5) | 5 (18.5) |
| N1 | 81 (41.8) | 64 (79.0) | 17 (21.0) | 108 (35.5) | 79 (73.1) | 29 (26.9) |
| N2 | 75 (38.7) | 56 (74.7) | 19 (25.3) | 130 (42.8) | 103 (79.2) | 27 (20.8) |
| N3 | 29 (14.9) | 23 (79.3) | 6 (20.7) | 39 (12.8) | 30 (76.9) | 9 (23.1) |
| TNM stage* | ||||||
| II | 21 (10.8) | 15 (71.4) | 6 (28.6) | 54 (17.8) | 43 (79.6) | 11 (20.4) |
| III | 106 (54.6) | 84 (79.2) | 22 (20.8) | 146 (48.0) | 112 (76.7) | 34 (23.3) |
| IV | 67 (34.5) | 53 (79.1) | 14 (20.9) | 104 (34.2) | 79 (76.0) | 25 (24.0) |
| EBV DNA (copies/mL) | ||||||
| ≥1500 | 102 (52.6) | 76 (74.5) | 26 (25.5) | NA | NA | NA |
| <1500 | 92 (47.7) | 76 (82.6) | 16 (17.4) | NA | NA | NA |
| ECOG | ||||||
| 0 | 15 (7.7) | 11 (73.3) | 4 (26.7) | 20 (6.6) | 15 (75.0) | 5 (25.0) |
| 1 | 172 (88.7) | 136 (79.1) | 36 (20.9) | 267 (87.8) | 205 (76.8) | 62 (23.2) |
| 2 | 7 (3.6) | 5 (71.4) | 2 (28.6) | 17 (5.6) | 14 (82.4) | 3 (17.6) |
| LDH concentration (U/L) | ||||||
| <245 | 177 (91.2) | 139 (78.5) | 38 (21.5) | 265 (87.2) | 209 (78.9) | 56 (21.1) |
| ≥245 | 17 (8.8) | 13 (76.5) | 4 (23.5) | 39 (12.8) | 25 (64.1) | 14 (35.9) |
| C reactive protein concentration (mg/L) | ||||||
| <3.0 | 131 (67.5) | 102 (77.9) | 29 (22.1) | 190 (62.5) | 148 (77.9) | 42 (22.1) |
| ≥3.0 | 63 (32.5) | 50 (79.4) | 13 (20.6) | 114 (37.5) | 86 (75.4) | 28 (24.6) |
| Hemoglobin concentration (g/L) | ||||||
| <130 | 44 (22.7) | 39 (88.6) | 5 (11.4) | 93 (30.6) | 71 (76.3) | 22 (23.7) |
| ≥130 | 150 (77.3) | 113 (75.3) | 37 (24.7) | 211 (69.4) | 163 (77.3) | 48 (22.7) |
| Body mass index (kg/m2) | ||||||
| <23.0 | 107 (55.2) | 83 (77.6) | 24 (22.4) | 177 (58.2) | 139 (78.5) | 38 (21.5) |
| ≥23.0 | 87 (44.8) | 69 (79.3) | 18 (20.7) | 127 (41.8) | 95 (74.8) | 32 (25.2) |
| Treatment method | ||||||
| CCRT | 78 (40.2) | 63 (80.8) | 15 (19.2) | 109 (35.9) | 83 (76.1) | 26 (23.9) |
| IC+CCRT | 89 (45.9) | 70 (78.7) | 19 (21.3) | 112 (36.8) | 87 (77.7) | 25 (22.3) |
| RT/IC+RT/CCRT+AC | 27 (13.9) | 19 (70.4) | 8 (29.6) | 83 (27.3) | 64 (77.1) | 19 (22.9) |
*According to the eighth edition of UICC/AJCC staging system.
AC, adjuvant chemotherapy; AJCC, American Joint Committee on Cancer; CCRT, concurrent chemoradiotherapy; EBV, Epstein–Barr virus; ECOG, Eastern Cooperative Oncology Group; IC, induction chemotherapy; LDH, serum lactate dehydrogenase; NA, not available; RT, radiotherapy; TNM, tumor–node–metastases; UICC, Union for International Cancer Control.