Table 1 The baseline characteristics of the primary cohort and the validation cohort
|  | The primary cohort (n = 95) No. of patients (%) | The validation cohort (n = 55) No. of patients (%) | P-value |
|---|---|---|---|
Sex | Â | Â | 0.579 |
 Male | 68 (71.6) | 37 (67.3) |  |
 Female | 27 (28.4) | 18 (32.7) |  |
Age (years) | Â | Â | 0.342 |
 Median | 58 | 59 |  |
 Range | 38–81 | 37–78 |  |
Esophagectomy | Â | Â | 0.729 |
 R0 | 87 (91.6) | 52 (94.5) |  |
 R1 | 8 (8.4) | 3 (5.5) |  |
Grade | Â | Â | 0.870 |
 G1 | 9 (9.5) | 4 (7.3) |  |
 G2 | 69 (72.6) | 40 (72.7) |  |
 G3 | 17 (17.9) | 11 (20.0) |  |
T Stage | Â | Â | 0.340 |
 T1a + T1b | 14 (14.7) | 7 (12.7) |  |
 T2 | 30 (31.6) | 18 (32.7) |  |
 T3 | 33 (33.7) | 25 (45.5) |  |
 T4a | 18 (19.0) | 5 (9.1) |  |
N Stage | Â | Â | 0.272 |
 N0 | 64 (67.4) | 29 (52.8) |  |
 N1 | 18 (18.9) | 13 (23.7) |  |
 N2 | 10 (10.5) | 11 (20.0) |  |
 N3 | 3 (3.2) | 2 (3.5) |  |
TNM Stage | Â | Â | 0.656 |
 IA + IB | 20 (21.0) | 8 (14.5) |  |
 IIA + IIB | 34 (35.8) | 20 (36.4) |  |
 IIIA+IIIB | 32 (33.7) | 23 (41.8) |  |
 IVA | 9 (9.5) | 4 (7.3) |  |