Characteristic | Training cohort (n = 196) | P value | Internal Validation cohort (n = 84) | P value | External Validation cohort (n = 71) | P value | |||
---|---|---|---|---|---|---|---|---|---|
Low Ki-67 expression (n = 104) | High Ki-67 expression (n = 92) | Low Ki-67 expression (n = 44) | High Ki-67 expression (n = 40) | Low Ki-67 expression (n = 38) | High Ki-67 expression (n = 33) | ||||
Age, years | Â | Â | 0.495 | Â | Â | 0.785 | Â | Â | 0.702 |
 < 60 | 48 (46.1) | 38 (41.3) |  | 20 (45.5) | 17 (42.5) |  | 19 (50.0) | 15 (45.5) |  |
 ≥ 60 | 56 (53.8) | 54 (58.7) |  | 24 (54.5) | 23 (57.5) |  | 19 (50.0) | 18 (54.5) |  |
Sex | Â | Â | 0.187 | Â | Â | 0.403 | Â | Â | 0.571 |
Male | 85 (81.7) | 68 (73.9) | Â | 33 (75.0) | 33 (82.5) | Â | 29 (76.3) | 27 (81.8) | Â |
Female | 19 (18.3) | 24 (26.1) | Â | 11 (25.0) | 7 (17.5) | Â | 9 (23.7) | 6 (18.2) | Â |
Smoking history | Â | Â | 0.767 | Â | Â | 0.749 | Â | Â | 0.592 |
No | 60 (57.7) | 55 (59.8) | Â | 26 (59.1) | 25 (62.5) | Â | 23 (60.5) | 22 (66.7) | Â |
Yes | 44 (42.3) | 37 (40.2) | Â | 18 (40.9) | 15 (37.5) | Â | 15 (39.5) | 11 (33.3) | Â |
Tumor location | Â | Â | 0.466 | Â | Â | 0.226 | Â | Â | 0.113 |
Oral cavity | 42 (40.4) | 33 (35.9) | Â | 20 (45.4) | 13 (32.5) | Â | 18 (47.4) | 10 (30.3) | Â |
Oropharynx | 11 (10.6) | 17 (18.5) | Â | 7 (15.9) | 4 (10.0) | Â | 6 (15.8) | 3 (9.1) | Â |
Larynx | 35 (33.6) | 28 (30.4) | Â | 15 (34.1) | 17 (42.5) | Â | 12 (31.6) | 13 (39.4) | Â |
Hypopharynx | 16 (15.4) | 14 (15.2) | Â | 2 (4.5) | 6 (15.0) | Â | 2 (5.3) | 7 (21.2) | Â |
Clinical T stage |  |  |  < 0.001 |  |  | 0.004 |  |  | 0.006 |
T1-T2 | 63 (60.6) | 24 (26.1) | Â | 28 (63.6) | 13 (32.5) | Â | 24 (63.2) | 10 (30.3) | Â |
T3-T4 | 41 (39.4) | 68 (73.9) | Â | 16 (36.4) | 27 (67.5) | Â | 14 (36.8) | 23 (69.7) | Â |
MR-reported LN status |  |  |  < 0.001 |  |  | 0.005 |  |  | 0.029 |
Negative | 78 (75.0) | 42 (45.7) | Â | 33 (75.0) | 18 (45.0) | Â | 27 (71.1) | 15 (45.5) | Â |
Positive | 26 (25.0) | 50 (54.3) | Â | 11 (25.0) | 22 (55.0) | Â | 11 (28.9) | 18 (54.5) | Â |