Table 1.
Parameter estimates
| Model parameter | Base-case value | Lower and upper values in sensitivity analysis | References |
|---|---|---|---|
|
Performance of screening tests | |||
| gFOBT sensitivity for adenomas |
11% |
10%, 12%1 |
[13-21] |
| gFOBT sensitivity for CRC |
36% |
31%, 42%1 |
|
| gFOBT specificity for adenomas and CRC |
97% |
96%, 98% |
|
| FIT sensitivity for adenomas |
21% |
19%, 22%1 |
[16,22-32] |
| FIT sensitivity for CRC |
71% |
67%, 75%1 |
|
| FIT specificity for adenomas and CRC |
95% |
94%, 96% |
|
| FSIG sensitivity for low-risk distal adenomas |
65% |
60%, 70%1 |
Expert opinion informed by [18,20,22] |
| FSIG sensitivity for intermediate/high-risk distal adenomas |
74% |
68%, 78%1 |
|
| FSIG sensitivity for distal CRC |
90% |
85%, 95%1 |
|
| FSIG specificity for distal adenomas and CRC |
92% |
90%, 95% |
|
|
Uptake and compliance with screening, diagnosis and surveillance | |||
| gFOBT uptake |
53% |
32%, 70% |
[34-37] |
| FIT uptake |
53% |
32%, 70% |
|
| FSIG uptake |
39% |
24%, 67% |
[38-40] |
| COL compliance (diagnostic test or adenoma surveillance) |
86% |
- |
[34,35] |
|
Performance of diagnostic tests and related parameters | |||
| COL sensitivity for low-risk adenomas |
77% |
- |
[41,42] |
| COL sensitivity for intermediate/high-risk adenomas |
98% |
- |
|
| COL sensitivity for CRC |
98% |
- |
|
| COL specificity for adenomas and CRC |
97% |
- |
Expert opinion |
| CTC sensitivity for low-risk adenomas |
53% |
- |
Expert opinion, informed by [43-46] |
| CTC sensitivity for intermediate/high-risk adenomas |
85% |
- |
|
| CTC sensitivity for CRC |
85% |
- |
|
| CTC specificity for adenomas and CRC |
86% |
- |
|
| Average number of adenomas removed per person |
1.9 |
- |
[47] |
| % of those with intermediate/high-risk adenomas removed in whom the adenoma was high-risk |
29% |
- |
[34] |
|
Harms of screening | |||
| FSIG probability of perforation (with or without polypectomy) |
0.002% |
- |
[38] |
| FSIG probability of death following perforation |
6.452% |
- |
[48] |
| Probability of (major) bleeding following FSIG |
0.029% |
- |
[38] |
| COL probability of perforation (with polypectomy) |
0.216% |
- |
[49] |
| COL probability of perforation (without polypectomy) |
0.107% |
- |
|
| COL probability of death following perforation |
5.195% |
- |
[48] |
| Probability of (major) bleeding following COL | 0.379% | - | [38] |
COL colonoscopy, CRC colorectal cancer, CTC CT colonography, FIT faecal immunochemical test, gFOBT guaiac faecal occult blood test, FSIG flexible sigmoidoscopy; low-risk adenoma(s), <10 mm; intermediate/high-risk adenoma(s), ≥10 mm. 1 parameters varied simultaneously in sensitivity analysis; - parameters not varied in sensitivity analyses.