Table 1 The differences of clinical data in both the training and test cohorts
Characteristic | Training cohort (n = 206) | Internal validation cohort (n = 88) | External validation cohort (n = 67) | ||||||
|---|---|---|---|---|---|---|---|---|---|
LNM− group (n = 155) | LNM+ group (n = 51) | p-value | LNM− group (n = 73) | LNM+ group (n = 15) | p-value | LNM− group (n = 44) | LNM+ group (n = 23) | p-value | |
Sex (%) | Â | Â | 0.867 | Â | Â | 0.024 | Â | Â | 0.788 |
 Female | 37 (23.9) | 13 (25.5) | 12 (16.4) | 7 (46.7) | 20 (45.5) | 10 (43.5) | |||
 Male | 118 (76.1) | 38 (74.5) | 61 (83.6) | 8 (53.3) | 24 (54.5) | 13 (56.5) | |||
Age (mean ± SD, years) | 62.8 ± 12.2 | 65.3 ± 8.9 | 0.654 | 60.3 ± 13.3 | 63.5 ± 10.3 | 0.707 | 58.3 ± 11.2 | 64.2 ± 10.8 | 0.025 |
Drinking history | Â | Â | 0.084 | Â | Â | 0.128 | Â | Â | 0.192 |
 No | 96 (61.9) | 39 (76.5) | 40 (54.8) | 12 (80.0) | 15 (34.1) | 4 (17.3) | |||
 Yes | 59 (38.1) | 12 (23.5) | 33 (45.2) | 3 (20.0) | 29 (65.9) | 19 (82.7) | |||
Smoking history | Â | Â | 0.249 | Â | Â | 0.058 | Â | Â | 0.107 |
 No | 84 (54.2) | 33 (64.7) | 31 (42.5) | 11 (73.3) | 18 (40.9) | 12 (36.4) | |||
 Yes | 71 (45.8) | 18 (35.3) | 42 (57.5) | 4 (26.7) | 26 (59.1) | 11 (63.6) | |||
Thick (mean ± SD, cm) | 1.3 ± 0.3 | 1.4 ± 0.4 | 0.054 | 1.4 ± 0.6 | 1.5 ± 0.9 | 0.907 | 1.1 ± 0.9 | 1.0 ± 1.8 | 0.752 |
Tumor location (%) | Â | Â | 0.934 | Â | Â | 0.618 | Â | Â | 0.258 |
 Upper lesion | 7 (4.5) | 2 (3.9) | 3 (4.1) | 1 (6.7) | 15 (34.1) | 10 (43.5) | |||
 Lower lesion | 99 (63.9) | 34 (66.7) | 53 (72.6) | 9 (60.0) | 12 (27.3) | 8 (34.8) | |||
 Middle lesion | 49 (31.6) | 15 (29.4) | 17 (23.3) | 5 (33.3) | 17 (38.6) | 5 (21.7) | |||
pT stage (%) | Â | Â | 0.157 | Â | Â | 0.197 | Â | Â | 0.927 |
 pT1 + T2 | 34 (21.9) | 6 (11.8) | 21 (28.8) | 1 (6.7) | 10 (22.7) | 3 (13.0) | |||
 pT3 | 107 (69.0) | 37 (72.5) | 48 (65.8) | 13 (86.7) | 20 (45.5) | 10 (43.5) | |||
 pT4 | 14 (9.0) | 8 (15.7) | 4 (5.5) | 1 (6.7) | 14 (31.8) | 10 (43.5) | |||
pN stage (%) | Â | Â | 0.015 | Â | Â | 0.033 | Â | Â | 0.886 |
 pN0 | 14 (9.0) | 11 (21.6) | 37 (50.7) | 3 (20.0) | 12 (27.3) | 8 (34.8) | |||
 pN1 | 42 (27.1) | 16 (31.4) | 25 (34.2) | 6 (40.0) | 10 (22.7) | 12 (52.2) | |||
 pN2 | 22 (14.2) | 12 (23.5) | 9 (12.3) | 6 (40.0) | 12 (27.3) | 2 (8.7) | |||
 pN3 | 7 (4.5) | 12 (23.5) | 2 (2.7) | 0 (0.0) | 10 (22.7) | 1 (4.3) | |||
PNI | Â | Â | 0.001 | Â | Â | 0.056 | Â | Â | 0.228 |
 No | 124 (80.0) | 25 (49.0) | 16 (21.9) | 5 (33.3) | 20 (45.5) | 10 (43.5) | |||
 Yes | 31 (20.0) | 26 (51.0) | 57 (78.1) | 10 (66.7) | 24 (54.5) | 13 (56.5) | |||
Differentiation | Â | Â | 0.014 | Â | Â | 0.045 | Â | Â | 0.928 |
 0 | 42 (27.1) | 14 (27.5) | 16 (21.9) | 5 (33.3) | 12 (27.3) | 12 (52.2) | |||
 1 | 113 (72.9) | 30 (58.8) | 57 (78.1) | 10 (66.7) | 20 (45.5) | 10 (43.5) | |||
 2 | 0 (0.0) | 4 (7.8) | 0 (0.0) | 0 (0.0) | 4 (9.1) | 1 (4.3) | |||
 3 | 0 (0.0) | 3 (5.9) | 0 (0.0) | 0 (0.0) | 8 (18.2) | 0 (0.0) | |||
The length of esophageal resection | Â | Â | 0.025 | Â | Â | 0.048 | Â | Â | 0.128 |
 ≤ 5 cm | 40 (25.8) | 6 (11.8) | 13 (17.8) | 1 (6.7) | 20 (45.5) | 13 (56.5) | |||
 > 5 cm | 115 (74.2) | 45 (88.2) | 60 (82.2) | 14 (93.3) | 24 (54.5) | 10 (43.5) | |||