| Cause | n (%) |
| Surveillance colonoscopy | 25 (17) |
| Non-surveillance colonoscopy | 35 (23) |
| Increase of symptoms* | 61 (41) |
| Incidental finding in colectomy specimen | 20 (13) |
| Refractory disease | 10 (7) |
| Proctectomy in IPAA procedure | 1 (1) |
| Toxic megacolon | 1 (1) |
| Stenosis | 1 (1) |
| Perforation after colonoscopy | 1 (1) |
| Dysplasia | 6 (4) |
| Suspected appendicitis† | 1 (1) |
| Suspected acute cholecystitis† | 1 (1) |
| Abnormal laboratory findings | 4 (3) |
| Unknown‡ | 2 (1) |
*Symptoms include increase of abdominal pain, altered bowel habits with or without rectal blood loss.
†CRC detected during laparotomy.
‡Referrals for proctocolectomy of which the initial cause of CRC diagnosis was irretrievable.
IPAA, ileal pouch anal anastomosis.