Table 2.
Patient characteristics in training cohort and validation cohort
| Characteristic | Training cohort (n=3,542) | Validation cohort (n=3,542) | p-value |
|---|---|---|---|
| Age (yr) | |||
| ≤ 46 | 1,801 (50.8) | 1,754 (49.5) | 0.274 |
| > 46 | 1,741 (49.2) | 1,788 (50.5) | |
| Sex | |||
| Female | 914 (25.8) | 929 (26.2) | 0.705 |
| Male | 2,628 (74.2) | 2,613 (73.8) | |
| T categorya) | |||
| T1 | 296 (8.4) | 301 (8.5) | 0.759 |
| T2 | 769 (21.7) | 733 (20.7) | |
| T3 | 1,689 (47.7) | 1,701 (48.0) | |
| T4 | 788 (22.2) | 807 (22.8) | |
| N categorya) | |||
| N0 | 666 (18.8) | 647 (18.3) | 0.959 |
| N1 | 1,258 (35.5) | 1,260 (35.6) | |
| N2 | 1,247 (35.2) | 1,272 (35.9) | |
| N3 | 289 (8.2) | 281 (7.9) | |
| PLN(+) | 82 (2.3) | 82 (2.3) | |
| EBV DNA level (copy/mL) | |||
| < 1,000 | 1,409 (39.8) | 1,391 (39.3) | 0.129 |
| 1,000-9,999 | 952 (26.9) | 913 (25.8) | |
| 10,000-99,999 | 728 (20.6) | 743 (21.0) | |
| 100,000-999,999 | 368 (10.4) | 375 (10.6) | |
| ≥ 1,000,000 | 85 (2.4) | 120 (3.4) | |
| Treatment group | |||
| RT alone | 619 (17.5) | 619 (17.5) | 0.707 |
| CCRT | 1,223 (34.5) | 1,215 (34.3) | |
| IC+RT | 741 (20.9) | 718 (20.3) | |
| IC+CCRT | 851 (24.0) | 894 (25.2) | |
| Others | 108 (3.0) | 96 (2.7) |
Values are presented as number (%). Pearson chi-square test was used to calculate the p-value. PLN, parotid lymph node; EBV, Epstein-Barr virus; RT, radiotherapy; CCRT, concurrent chemoradiotherapy; IC, induction chemotherapy.
a)
According to the 8th edition of International Union Against Cancer/American Joint Committee on Cancer staging system.