Table 1.
Baseline characteristics of study sets.a
| Characteristics | Training set (n = 300) |
Internal test set (n = 89) |
External test set 1 (n = 120) |
External test set 2 (n = 44) |
P valuec |
|---|---|---|---|---|---|
| Age (years)b | 62 (56–68) | 62 (55–67) | 62 (55–66) | 62 (57–68) | 0.82 |
| Sex | 0.063 | ||||
| Female | 11 (4) | 5 (6) | 1 (1) | 4 (9) | |
| Male | 289 (96) | 84 (94) | 119 (99) | 40 (91) | |
| Primary site | <0.0001 | ||||
| Glottic | 44 (15) | 11 (12) | 36 (30) | 17 (39) | |
| Supraglottic | 256 (85) | 78 (88) | 84 (70) | 27 (61) | |
| T stage | <0.0001 | ||||
| T1 | 96 (32) | 31 (35) | 33 (28) | 2 (5) | |
| T2 | 117 (39) | 34 (38) | 52 (43) | 6 (13) | |
| T3 | 67 (22) | 19 (21) | 29 (24) | 15 (34) | |
| T4 | 20 (7) | 6 (6) | 6 (5) | 21 (48) | |
| Differentiation status | 0.082 | ||||
| Well | 84 (28) | 33 (37) | 36 (30) | 7 (16) | |
| Moderate | 179 (60) | 46 (52) | 61 (51) | 28 (64) | |
| Poor or undifferentiated | 37 (12) | 10 (11) | 23 (19) | 9 (20) | |
| Radiological features-paraglottic/preepiglottic space invasion | 0.072 | ||||
| None | 259 (86) | 67 (75) | 96 (80) | 37 (84) | |
| Yes | 41 (14) | 22 (25) | 24 (20) | 7 (16) | |
| Radiological features-cartilage invasion | 0.47 | ||||
| None | 292 (97) | 85 (96) | 108 (90) | 42 (95) | |
| Yes | 8 (3) | 4 (4) | 12 (10) | 2 (5) | |
| Radiological features-maximum tumor diameter (cm)b | 3.2 (0.7–5.7) | 3.6 (1.2–6.6) | 3.7 (1.3–6.5) | 4.6 (0.5–8.1) | 0.22 |
| Radiological features-enhancement pattern | 0.55 | ||||
| Homogenous enhancement | 231 (77) | 72 (81) | 90 (75) | 32 (73) | |
| Inhomogeneous enhancement | 69 (23) | 17 (19) | 30 (25) | 12 (27) | |
| Pathological LNM | 124 (41) | 33 (37) | 42 (35) | 11 (25) | 0.17 |
Abbreviation: LNM, lymph node metastasis.
a
Unless otherwise indicated, data are numbers of patients, and data in parentheses are percentage.
b
Data are means, with IQRs in parentheses.
c
P value was calculated by Chi-square test or t-test.