Modified Kadish Staging System
| Stage | Description |
| A | Tumor confined to nasal cavity |
| B | Tumor confined to nasal cavity and paranasal sinuses |
| C | Tumor extent beyond nasal cavity and paranasal sinuses, including involvement of cribriform plate, base of skull, orbits, and intracranial cavity |
| D | Tumor with metastasis to cervical lymph nodes or distant site |
Adapted from Kadish et al. (3) and Morita et al. (6).