Comparison of 20103 and 20201 risk stratifications of participants in the Northern Ireland bowel cancer screening programme, for those having polyp specimens submitted at index colonoscopy (n=3122)
| 2020 surveillance algorithm | 2010 surveillance algorithm | ||||
| High risk (%) (1 year) | Intermediate risk (%) (3 years) | Low risk (%) (5 years) | No risk (%) (no surveillance) | Totals (%) | |
| High risk (3 years) | 316 (100) | 268 (29.5) | 24 (1.8) | 1 (0.2) | 609 (19.5)* |
| Not high risk (no surveillance) | 0 (0.0) | 640 (70.5) | 1296 (98.2) | 577 (99.8) | 2513 (80.5) |
| Totals (%) | 316 (10.1) | 908 (29.1) | 1320 (42.3) | 578 (18.5) | 3122 (100) |
*These 609 high-risk cases under 2020 guidance (see ref. 1 for definitions) comprise: 371 cases with advanced polyp (AP) plus 1–3 other premalignant polyps (PMP) but total <5; 114 cases with ≥5 PMPs but no APs; 101 cases with ≥5 PMPs and at least 1 AP; 23 cases with an isolated large (≥20 mm), large non-pedunculated colorectal polyp and no other PMPs.