| Total | |
| (n = 23) | |
| Mean resected specimen length, cm | 4.6 (1.5–9.5) |
| En block resection | 23 (100%) |
| En block plus R0 resection | 19 (82.6%) |
| Positive horizontal margins | 0 |
| Positive vertical margins | 4 (17.4%) |
| The depth of tumor invasion | |
| SM1 | 4 (17.4%) |
| SM2 | 19 (82.6%) |
| Mean depth of SM invasion, mm (range) | 0.79 (0.1-1.6) |
| Histological grading | |
| G1 | 0 |
| G2 | 9 (39.1%) |
| G3 | 14 (60.9%) |
| Presence of lymphovascular invasion | 4 (17.4%) |