Table 2.
Pathologic features of primary colorectal cancer n (%)
| Feature | Lung metastasis (n = 30) | Benign (n = 10) | P value |
| Primary tumor site | 0.001 | ||
| Colon | 4 (13.3) | 7 (70.0) | |
| Rectum | 26 (86.6) | 3 (30.0) | |
| Primary tumor size, cm | 5.2 ± 1.5 | 5.7 ± 2.9 | 0.505 |
| T stage | 0.015 | ||
| Tis | 0 | 1 (10.0) | |
| T1 | 0 | 1 (10.0) | |
| T2 | 1 (3.3) | 0 | |
| T3 | 28 (93.3) | 5 (50.0) | |
| T4 | 1 (3.3) | 3 (30.0) | |
| N stage | 0.001 | ||
| N0 | 5 (16.6) | 8 (80.0) | |
| N1 | 17 (26.6) | 2 (20.0) | |
| N2 | 8 (26.6) | 0 | |
| TNM stage | 0.011 | ||
| 0 | 0 | 1 (10.0) | |
| I | 1 (3.3) | 1 (10.0) | |
| II | 3 (10.0) | 5 (50.0) | |
| III | 16 (53.4) | 2 (20.0) | |
| IV | 10 (33.3) | 1 (10.0) | |
| Metastatic LN (n) | 33 ± 23 | 22 ± 9 | 0.034 |
| LN ratio1 | 0.171 ± 0.155 | 0.031 ± 0.072 | 0.009 |
| Histologic differentiation | 0.195 | ||
| WD | 0 | 1 (10.0) | |
| MD | 26 (86.6) | 8 (80.0) | |
| PD | 3 (10.0) | 0 | |
| Mucinous | 1 (3.3) | 1 (10.0) | |
| Lymphatic invasion | 22 (73.3) | 2 (20.0) | 0.005 |
| Vascular invasion | 4 (13.3) | 1 (10.0) | 0.633 |
| Perineural invasion | 5 (16.6) | 1 (10.0) | 0.526 |
| Adjuvant chemotherapy | 23 (76.7) | 3 (30.0) | 0.048 |
1
Involved LN (n)/total LN (n). LN: Lymph node; MD: Moderately differentiated; PD: Poorly differentiated; TNM: Tumor-node-metastasis; WD: Well differentiated.