Table 1.
Characteristics of Original and Validation Datasets
| Characteristic | Original patients (n=85) | Validation patients (n=83) | p-value* | All patients (n=168) |
|---|---|---|---|---|
| Age - median (range) | 57 (14–86) | 59 (35–89) | 0.06 | 58 (14–89) |
| Gender | ||||
| Female | 12 (14) | 7 (8) | 19 (11) | |
| Male | 73 (86) | 76 (92) | 0.33 | 149 (89) |
| T-classification | ||||
| T0 | 2 (2) | - | 2 (1) | |
| T1 | 12 (14) | 20 (24) | 32 (19) | |
| T2 | 25 (29) | 26 (31) | 51 (30) | |
| T3 | 18 (21) | 24 (29) | 42 (25) | |
| T4 | 28 (33) | 13 (16) | 0.05 | 41 (24) |
| N-classification | ||||
| N0 | 10 (12) | 9 (11) | 19 (11) | |
| N1 | 6 (7) | 11 (13) | 17 (10) | |
| N2 | 59 (69) | 56 (67) | 115 (68) | |
| N3 | 10 (12) | 7 (8) | 0.37 | 17 (10) |
| Tumor site | ||||
| Oropharynx | 45 (53) | 64 (77) | 109 (65) | |
| Larynx | 4 (5) | 6 (7) | 10 (6) | |
| Hypopharynx | 8 (9) | 5 (6) | 13 (8) | |
| Nasopharynx | 22 (26) | 8 (10) | 30 (18) | |
| Oral Cavity | 4 (5) | - | 4 (2) | |
| Unknown primary | 2 (2) | - | 0.003 | 2 (1) |
| p16INK4a status (oropharynx subset only) | ||||
| Positive | 17 (33) | 47 (73) | 64 (59) | |
| Negative | 2 (4) | 8 (13) | 1.00** | 10 (9) |
| Unknown | 33 (63) | 9 (14) | 35 (32) | |
| Pathology grade | ||||
| Low | 2 (2) | 2 (2) | 4 (2) | |
| Medium | 29 (34) | 31 (37) | 60 (36) | |
| High | 44 (52) | 35 (42) | 79 (47) | |
| Unknown | 10 (12) | 15 (18) | 0.4 | 25 (15) |
| Karnofsky performance status | ||||
| ≤60 | 2 (2) | 1 (1) | 3 (2) | |
| 70 | 9 (11) | 7 (8) | 16 (10) | |
| 80 | 14 (16) | 22 (27) | 36 (21) | |
| 90 | 59 (69) | 43 (52) | 102 (61) | |
| 100 | 1 (1) | 3 (4) | 4 (2) | |
| Unknown | - | 7 (8) | 0.45 | 7 (4) |
*
p-value refers to the difference between the original and validation patients. Continuous variables (age) were analyzed with a t-test; nominal variables (age, tumor site, p16INK4a status) were analyzed with Fisher’s exact tests; and ordinal variables (tumor stage, nodal stage, KPS, pathology grade) were analyzed with Wilcoxon rank-sum tests.
**
this comparison refers only to patients with known p16INK4a status.