Table 1. Parameter estimates, with base-case values, ranges and distributions.
Model parameter | Base-case | Range for SA | Distribution for PSAa | Source |
---|---|---|---|---|
Performance of screening tests | ||||
gFOBT sensitivity for adenomas | 11% | 10–12% | Beta (11.40, 92.10) | Allison et al, 1990; Castiglione et al, 1991; Foley et al, 1992; Allison et al, 1996; Brevinge et al, 1997; Lieberman and Weiss, 2001; Niv et al, 2002; Sung et al, 2003 Collins et al, 2005 |
gFOBT sensitivity for CRC | 36% | 31–42% | Beta (105.00, 186.60) | |
gFOBT specificity for adenomas and CRC | 97% | 96–98% | Beta (1083.40, 33.50) | |
FIT sensitivity for adenomas | 21% | 19–22% | Beta (594.62, 2236.92) | Allison et al, 1996; Itoh et al, 1996; Chen et al, 1997; Nakama et al, 2000; Nakama et al, 2001; Cheng et al, 2002; Gondal et al, 2003; Liu et al, 2003; Morikawa et al, 2005; Nakazato et al, 2006; Allison et al, 2007; Morikawa et al, 2007 |
FIT sensitivity for CRC | 71% | 67–75% | Beta (35.29, 143.08) | |
FIT specificity for adenomas and CRC | 95% | 94–96% | Beta (1732.57, 91.19) | |
FSIG sensitivity for low-risk distal adenomas | 65% | 60–70% | Beta (235.00, 126.54) | Expert opinion informed by Rozen et al, 1987; Lieberman and Weiss, 2001; Sung et al, 2003 |
FSIG sensitivity for intermediate/high-risk distal adenomas | 74% | 68–78% | Beta (180.00, 63.24) | |
FSIG sensitivity for distal CRC | 90% | 85–95% | Beta (90.00, 10.00) | |
FSIG specificity for distal adenomas and CRC | 92% | 90–95% | Beta (250.00, 21.74) | |
Uptake and compliance with screening and diagnostic tests | ||||
gFOBT uptake | 53% | 32–70% | Uniform (32%, 70%) | Weller et al, 2006; Information Services Division, 2008 |
FIT uptake | 53% | 32–70% | Uniform (32%, 70%) | |
FSIG uptake | 39% | 24–67% | Uniform (24%, 67%) | UK Flexible Sigmoidoscopy Screening Trial Investigators, 2002 |
% of individuals who never accept an offer of screeningb | 13% | 0–41% | — | Weller et al, 2006 |
COL compliance (diagnostic test) | 86% | 81–90% | Uniform (81%, 90%) | Weller et al, 2006; Information Services Division, 2008 |
Performance of diagnostic tests and related parameters | ||||
COL sensitivity for low-risk adenomas | 77% | 73–80% | Beta (350.00, 104.55) | van Rijn et al, 2006 Bressler et al, 2007 |
COL sensitivity for intermediate/high-risk adenomas | 98% | 93–99% | Uniform (93%, 99%) | |
COL sensitivity for CRC | 98% | 95%–99% | Uniform (95, 99%) | |
COL specificity for adenomas and CRC | 97% | 96–98% | Beta (970.00, 30.00) | Expert opinion |
CTC sensitivity for low-risk adenomas | 53% | 45–60% | Beta (80.00, 70.94) | Expert opinion, informed by Cotton et al, 2004; Halligan et al, 2005; Mulhall et al, 2005; Johnson et al, 2008 |
CTC sensitivity for intermediate/high-risk adenomas | 85% | 48–100% | Beta (4.50, 0.79) | |
CTC sensitivity for CRC | 85% | 75–95% | Beta (50.00, 8.82) | |
CTC specificity for adenomas and CRC | 86% | 80–90% | Beta (140.00, 22.79) | |
Average number of adenomas removed per person | 1.9 | — | — | Winawer et al, 1993 |
Surveillance of screening-detected adenomas | ||||
% of those in with intermediate/high-risk adenomas removed in whom the adenoma was high-risk | 29% | — | — | Alexander and Weller, 2003; Weller et al, 2006 |
COL compliance (surveillance) | 86% | 81–90% | Uniform (81%, 90%) | Assumption based on Weller et al, 2006; Information Services Division, 2008 |
Harms of screening | ||||
FSIG probability of perforation (with or without polypectomy) | 0.002% | 0–0.051% | Uniform (0%, 0.051%) | UK Flexible Sigmoidoscopy Screening Trial Investigators, 2002 |
FSIG probability of death following perforation | 6.452% | 0–9.070% | Uniform (0%, 9.070%) | Gatto et al (2003) |
Probability of (major) bleeding following FSIG | 0.029% | 0.002–0.054% | Uniform (0.002%, 0.054%) | UK Flexible Sigmoidoscopy Screening Trial Investigators, 2002 |
COL probability of perforation (with polypectomy) | 0.216% | 0.168–0.298% | Uniform (0.168%, 0.298%) | Dafnis et al, 2001 |
COL probability of perforation (without polypectomy) | 0.107% | 0.010–0.249% | Uniform (0.010%, 0.249%) | |
COL probability of death following perforation | 5.195% | 0–9.070% | Uniform (0%, 9.070%) | Gatto et al (2003) |
Probability of (major) bleeding following COL | 0.379% | 0.065–0.412% | Uniform (0.065%, 0.412%) | UK Flexible Sigmoidoscopy Screening Trial Investigators, 2002 |
Health-related QoL | ||||
Utility: cancer free | 0.94 | — | — | Fryback and Lawrence (1997) |
Utility: stage I, II, III, IV cancer | 0.80 | 0.43–0.94 | 0.94*Beta (3.92, 0.69) | Ramsey et al (2000) |
Costs | ||||
gFOBT kitc | €1.70 | €1.36–€2.04 | Uniform (€1.36, €2.04) | Estimated by authors |
gFOBT processing/analysisd | €7.81 | €6.25–€9.37 | Uniform (€6.25, €9.37) | |
FIT kitc | €3.75 | €3–€4.50 | Uniform (€3, €4.50) | |
FIT processing/analysisd | €11.60 | €9.28–€13.92 | Uniform (€9.28, €13.92) | |
Cost of FSIG (with/without polypectomy) | €150 | €120–€180 | Uniform (€120, €180) | Whynes et al, 2003; VHI Healthcare |
Cost of COL | €650 | €520–€780 | Uniform (€520, €780) | HSE Casemix Unit, 2008 |
Cost of CTC | €550 | €440–€660 | Uniform (€440, €660) | Expert opinion |
Cost of treating bowel perforation | €10 200 | €8160–€12 240 | Uniform (€8160, €12 240) | HSE Casemix Unit, 2008 |
Cost of admittance for bleeding | €3079 | €2463–€3695 | Uniform (€2463, €3695) | |
Pathology cost for adenoma | €65 | €52–€78 | Uniform (€52, €78) | Tappenden et al, 2004 |
Pathology cost for cancer | €530 | €424–€636 | Uniform (€424, €636) | |
Lifetime cost stage I CRC-symptomatic | €23 688 | €18 950–€28 425 | Uniform (€18 950, €28 425) | Tilson et al, 2011 |
Lifetime cost stage II CRC-symptomatic | €37 180 | €29 744–€44 616 | Uniform (€29 744, €44 616) | |
Lifetime cost stage III CRC-symptomatic | €48 835 | €39 068–€58 602 | Uniform (€39 068, €58 602) | |
Lifetime cost stage IV CRC-symptomatic | €36 602 | €29 281–€43 922 | Uniform (€29 281, €43 922) | |
Lifetime cost stage I CRC-screen-detected | €22 885 | €18 308–€27 462 | Uniform (€18 308, €27 462) | |
Lifetime cost stage II CRC-screen-detected | €36 377 | €29 102–€43 652 | Uniform (€29 102, €43 652) | |
Lifetime cost stage III CRC-screen-detected | €48 032 | €38 426–€57 638 | Uniform (€38 426, €57 638) | |
Lifetime cost stage IV CRC-screen-detected | €35 799 | €28 639–€42 959 | Uniform (€28 639, €42 959) | |
Discount rate | ||||
Discount rate for costs and benefits | 4% | 0–6% | — | Recommended for Ireland |
Abbreviations: COL=colonoscopy; CRC=colorectal cancer; CTC=CT colonography; FIT=faecal immunochemical test; FSIG=flexible sigmoidoscopy; gFOBT=guaiac-based faecal occult blood test; PSA=probabilistic sensitivity analysis; SA=sensitivity analysis; low-risk adenoma(s), <10 mm; intermediate/high-risk adenoma(s), ⩾10 mm.
if no distribution given, parameter was not varied in the PSA.
relevant to gFOBT and FIT scenarios only.
cost per kit dispatched (i.e., cost per individual invited to participate in screening).
cost per kit completed and returned (i.e., cost per screening participant).