Table 1.
Clinicopathological characteristics of EGC patients in the training set and the validation set
| Parameter | Training set | Validation set | P-value |
|---|---|---|---|
| (n = 1460) | (n = 172) | ||
| n (%) | n (%) | ||
| Age (mean ± SD) | 57.43 ± 11.5 | 66.6 ± 10.6 | < 0.001 |
| Age | < 0.001 | ||
| ≤ 60 | 815 (55.8) | 49 (28.5) | |
| > 60 | 645 (44.2) | 123 (71.5) | |
| Sex | < 0.001 | ||
| Male | 1024 (70.1) | 94 (54.7) | |
| Female | 436 (29.9) | 78 (45.3) | |
| Tumor location | 0.004 | ||
| Upper | 242 (16.6) | 28 (16.3) | |
| Middle | 475 (32.5) | 58 (33.7) | |
| Lower | 643 (44.0) | 86 (50.0) | |
| Overlapa | 100 (6.8) | 0 (0) | |
| Tumor size (mm, mean ± SD) | 24.7 ± 15.4 | 27.8 ± 16.2 | 0.016 |
| Tumor size | < 0.001 | ||
| ≤ 20 mm | 850 (58.2) | 67 (39.0) | |
| > 20 mm | 610 (41.8) | 105 (61.0) | |
| Depth of invasion | < 0.001 | ||
| Mucosa | 641 (43.9) | 100 (58.1) | |
| Submucosa | 819 (56.1) | 72 (41.9) | |
| Tumor histological types | < 0.001 | ||
| Differentiated | 502 (34.4) | 122 (70.9) | |
| Undifferentiated | 958 (65.6) | 50 (29.1) | |
| No. of ELNs (mean ± SD) | 28.70 ± 11.5 | 25.70 ± 11.5 | 0.001 |
| N stage | 0.015 | ||
| N0 | 1189 (81.4) | 153 (89.0) | |
| N+ | 271 (18.6) | 19 (11.0) | |
| Extent of lymphadenectomy | < 0.001 | ||
| D1 | 155 (10.6) | 28 (16.3) | |
| D1+ | 209 (14.3) | 39 (22.7) | |
| D2 | 1096 (75.1) | 105 (61.0) | |
| LNM/LVI | 0.032 | ||
| Absent | 1145 (78.4) | 147 (85.5) | |
| Present | 315 (21.6) | 25 (14.5) |
Abbreviations: SD standard deviation, LNM lymph node metastasis, No. of ELNs number of examined lymph nodes, LVI lymphovascular invasion
aOverlap, tumor invaded two or more regions simultaneously