Table 3 Relationships between pathological factors and lymph node metastasis of patients with penile cancer
Variable | Training cohort (n = 411) | External validation cohort (n = 436) | ||||||
|---|---|---|---|---|---|---|---|---|
N0 [cases (%)] | N + [cases (%)] | χ2 | P | N0 [cases (%)] | N + [cases (%)] | χ2 | P | |
Lymphovascular embolization |  |  | 12.12 | < 0.001 |  |  | 61.32 | < 0.001 |
 Yes | 30 (42.9) | 40 (57.1) |  |  | 49 (52.7) | 44 (47.3) |  |  |
 No | 222 (65.1) | 119 (35.0) |  |  | 304 (88.7) | 39 (11.3) |  |  |
Perineural invasion |  |  | 11.20 | < 0.001 |  |  | 1.54 | 0.214 |
 Yes | 23 (41.1) | 33 (58.9) |  |  | 49 (72.1) | 16 (27.9) |  |  |
 No | 229 (64.5) | 126 (35.5) |  |  | 304 (81.9) | 67 (18.1) |  |  |
Pathological grade |  |  | 16.12 | < 0.001 |  |  | 2.89 | 0.069 |
 G1–2 | 243 (64.1) | 136 (35.9) |  |  | 272 (82.9) | 56 (17.1) |  |  |
 G3 | 9 (28.1) | 23 (71.9) |  |  | 81 (75.0) | 27 (25.0) |  |  |