European Neuroendocrine Tumour Society staging system. TNM, tumour, node, metastases18 with 5-year survival19
| Stage | TNM | 5-year survival19 (%) |
| I | T1 (<2 cm) | 100 |
| II | T2 (2–4 cm) T3 (>4 cm) Duodenum/bile duct | 85 |
| III IIIb | T4 Organ artery vessel invasion T×N1 | 85 |
| IV | T×N×M1 | 57 |
TNM, tumour, node, metastases with 5-year survival.