Table 1 Patients’ Demographic Information and Radiological Features
Characteristics | Training cohort (n = 84) | Internal validation cohort (n = 43) | External validation cohort (n = 39) | p |
|---|---|---|---|---|
Age, years (mean ± std) | 61.6 ± 7.1 | 61.6 ± 9.1 | 60.2 ± 7.6 | 0.626 |
Sex, case (%) | Â | Â | Â | 0.158 |
 Male | 74 (88.1) | 33 (76.7) | 35 (89.7) |  |
 Female | 10 (11.9) | 10 (23.3) | 4 (10.3) |  |
BMI (kg/m2) (mean ± std) | 22.9 ± 3.0 | 22.8 ± 3.3 | 22.4 ± 2.7 | 0.694 |
Clinical T stage, case (%) | Â | Â | Â | 0.229 |
 T2 | 7 (8.3) | 5 (11.6) | 8 (20.5) |  |
 T3 | 50 (59.5) | 29 (67.5) | 19 (48.7) |  |
 T4 | 27 (32.2) | 9 (20.9) | 12 (30.8) |  |
Clinical N stage, case (%) | Â | Â | Â | 0.700 |
 N0 | 10 (11.9) | 9 (20.9) | 7 (17.9) |  |
 N1 | 31 (36.9) | 15 (34.9) | 11 (28.2) |  |
 N2 | 38 (45.2) | 15 (34.9)) | 17 (43.6) |  |
 N3 | 5 (6.0) | 4 (9.3) | 4 (10.3) |  |
Clinical stage, case (%) | Â | Â | Â | 0.188 |
 II | 7 (8.3) | 8 (18.6) | 9 (23.1) |  |
 III | 47 (56.0) | 24 (55.8) | 18 (46.2) |  |
 IV | 30 (35.7) | 11 (25.6) | 12 (30.7) |  |
Tumor thickness (mm) | 16.6 ± 6.4 | 15.2 ± 6.7 | 17.8 ± 6.5 | 0.188 |
Tumor length (mm) | 48.4 ± 21.1 | 49.6 ± 18.6 | 56.5 ± 18.0 | 0.101 |
No. of metastatic LN (n, (quartiles)) | 3 (1,4) | 2 (1,4) | 2 (1,4) | 0.873 |
LN-long (mm) | 22.4 ± 12.0 | 20.4 ± 11.0 | 17.0 ± 9.5 | 0.083 |
LN-short (mm) | 17.1 ± 9.7 | 15.4 ± 9.4 | 12.4 ± 7.0 | 0.058 |