TNM clinical classification 31
| T: Primary tumour | |
| T1 | Tumour invades lamina propria or submucosa |
| T2 | Tumour invades muscularis propria |
| T3 | Tumour invades adventitia |
| T4 | Tumour invades adjacent structures |
| N: Regional lymph nodes | |
| NX | Regional lymph nodes cannot be assessed |
| N0 | No regional lymph node metastasis |
| N1 | Regional lymph node metastasis |
| M: Distant metastasis | |
| MX | Distant metastasis cannot be assessed |
| M0 | No distant metastasis |
| M1 | Distant metastasis |
| For tumours of the lower thoracic oesophagus | |
| M1a | Metastasis in coeliac lymph nodes |
| M1b | Other distant metastasis |
| For tumours of the upper thoracic oesophagus | |
| M1a | Metastasis in cervical lymph nodes |
| M1b | Other distant metastasis |
| For tumours of the mid-thoracic oesophagus | |
| M1a | Not applicable |
| M1b | Non-regional lymph node or other distant metastasis |
| pTNM pathological classification | |
| The pT, pN, and pM categories correspond to the T, N, and M categories | |