1998 WHO/ISUP grading system. Characteristics and outcome of different grades: grading of recurrent tumours by modified 1973 WHO6,8 and staging by TNM16
| First recurrence | First progression | |||||||
|---|---|---|---|---|---|---|---|---|
| Grade of primary tumour (1998 WHO/ISUP)10 | N | Mean time to recurrence (months) | Grade | N | Stage | N | Stage | N |
| ISUP, International Society of Urologic Pathology; WHO, World Health Organisation. | ||||||||
| Papilloma | 18 | 61 | 1 | 1 | Ta | 3 | Tis | 0 |
| 2a | 1 | T1 | 0 | T1 | 0 | |||
| 2b | 1 | T2 | 0 | T2 | 0 | |||
| 3 | 0 | Tis | 0 | |||||
| Low malignant potential | 116 | 30 | 1 | 5 | Ta | 28 | Tis | 0 |
| 2a | 22 | T1 | 1 | T1 | 2 | |||
| 2b | 1 | T2 | 1 | T2 | 1 | |||
| 3 | 2 | Tis | 0 | |||||
| Low grade carcinoma | 141 | 20 | 1 | 8 | Ta | 39 | Tis | 1 |
| 2a | 26 | T1 | 2 | T1 | 4 | |||
| 2b | 8 | T2 | 1 | |||||
| 3 | 1 | Tis | 1 | |||||
| High grade carcinoma | 45 | 20 | 1 | 1 | Ta | 16 | Tis | 0 |
| 2a | 4 | T1 | 1 | T1 | 1 | |||
| 2b | 11 | T2 | 1 | T2 | 1 | |||
| 3 | 2 | Tis | 0 | |||||