Table 3.
Study type | Incidence of CRC | Time duration of FU in years | Presented with CRC | CRC developed at FU | Risk of CRC at time in years | Risk Factors | LGD | HGD | Detected on surveillance/symptoms |
Retrospective[91] | 8/436 (1.8%) | 12.1 (7-25) | 4 | 4 (2/4 after 7, 8 yr of FU) | Pancolitis 6/8 (66.7%) | NM | NM | Symptoms | |
Retrospective[90] | 5/532 (0.94%) | 25 | 0 | 5 (in FU of 6 yr) | 0 at 10, 2.3% (4.4% for pancolitis) at 20, 5.8% (10.2% for pancolitis) at > 20 | Pancolitis, disease duration > 10 yr | 2 progressed to CRC (1 after 5 yr, 1 at a different site after 1 yr). 6 did not progress in 1- 2 1/2 yr | 2 (1 CRC after 3 yr, another operated immediately) | 2 CRC on routine surveillance |
Partly Retrospective, partly prospective[1] | 5/50 (10%), [0/21 (prospective), 5/19 (retrospective)] | 9.35 (1-30), prospective 4.5 (1-12), retrospective 15 (8-30) | 0 | 5 (1 after 10 yr, 4 after 20 yr) | 0 at 10, 1% at 20, 7% at > 20 | Disease duration > 10 yr | No surveillance | No surveillance | 5 at symptoms |
Prospective[93] | 12/430 (2.8%) | Median 6 (1-39) | 0 | After median 18 yr from onset (6-27), 3 at 6, 6, 7 yr FU | Incidence density per 103 PYD was 2.3 at 10, 3.3 at 20 , 7 at > 20 | Pancolitis, longer disease duration | NM | NM | 1 on surveillance after 11 yr/11 at symptoms, (unifocal in 10 and multifocal in 2) |
Prospective surveillance study[92] | 1/29 (3.4%) | 10 (7.5-14.5) | 0 | 1 (after 1 yr) | Pancolitis in 55% | 5 at baseline, 3 new cases on surveillance | 3 (1 CRC after 1 yr) | 1 over 42 mo surveillance |
CRC: Colorectal cancer; FU: Follow up; LGD: Low grade dysplasia; HGD: High grade dysplasia; PYD: Person years of disease duration; NM: Not mentioned.