| TYPES OF WITHDRAWALS | FREQUENCY | PERCENTAGE (%) |
| Endoscopic biopsies | 101 | 77.1 |
| Surgical samples | 22 | 16.8 |
| Excision biopsies | 4 | 3.1 |
| Not specified | 4 | 3.1 |
| TOTAL | 131 | 100 |