Subclassification of T1a and T1b oesophageal adenocarcinoma
| Class | Description |
|---|---|
| T1a | |
| m1 | Carcinoma in situ or with questionable invasion beyond the basement membrane |
| m2 | Invasion into the lamina propria |
| m3 | Invasion into the muscularis mucosa |
| T1b | |
| sm1 | Invasion into the upper third of the submucosa within 500 µm |
| sm2 | Invasion into the middle third of the submucosa |
| sm3 | Invasion into the lower third of the submucosa |