Table 1 Model parameters and assumptions

Natural history

 Prevalence of low risk polyp (based on age)

At age 50, 0.2

0.15–0.25

[15,16,17]

At age 60, 0.4

0.35–0.45

At age 70, 0.5

0.45–0.55

 Prevalence of high risk polyp (based on age)

At age 50, 0.05

0.03–0.07

[15,16,17]

At age 60, 0.09

0.07–0.12

At age 70, 0.16

0.14–0.18

At age 80, 0.21

0.20–0.22

 Prevalence of preclinical early CRC at age 50

0.0024

0.002–0.0026

[15,16,17]

 Prevalence of preclinical regional CRC at age 50

0.0012

0.0008–0.0014

[15,16,17]

 Prevalence of preclinical distant CRC at age 50

0.0004

0.0003–0.0005

[15,16,17]

Yearly transition probabilities

 Normal mucosa to low risk polyp (based on age)

At age 50, 0.00836

± 10%

[15,16,17]

At age 55, 0.0099

At age 60, 0.01156

At age 65, 0.0133

At age 70, 0.01521

 Low risk polyp to high risk polyp

0.036

0.025–0.047

[15,16,17]

 High risk polyp to preclinical local cancer

0.042

0.03–0.051

[15,16,17]

 Preclinical local cancer to preclinical regional cancer

0.17

0.12–0.22

[15,16,17]

 Preclinical regional to preclinical distal

0.10

0.05–0.15

[15,16,17,18]

 Preclinical local to clinical local

0.17

0.12–0.23

[15,16,17,18]

 Preclinical regional to clinical regional

0.21

0.16–0.26

[15,16,17,18]

 Preclinical distant to clinical distal

1

N/A

[15,16,17,18]

Cancer mortality 5 year standard adherence

 Localized

0.1

N/A

[19]

 Regional

0.35

N/A

[19]

 Disseminated

0.92

N/A

[19]

Adherence with screening guidelines

 FOBT

0.75

0.4–0.8

[20,21,22]

 Sigmoidoscopy with FOBT

0.75

0.4–0.8

[20,21,22]

 Colonoscopy

0.8

0.4–0.8

[20,21,22]

 Colonoscopy after positive screening test

0.84

0.4–0.9

[20,21,22]

Test characteristics

 FOBT sensitivity low risk polyp

0.03

0.01–0.1

[23, 24]

 FOBT sensitivity high risk polyp

0.34

0.2–0.5

[23, 24]

 FOBT sensitivity cancer

0.72

0.5–0.85

[23, 24]

 FOBT specificity

0.91

0.7–0.96

[23, 24]

 Colonoscopy/sigmoidoscopy sensitivity low risk polyp

0.92

0.75–0.95

[25,26,27,28]

 Colonoscopy/sigmoidoscopy sensitivity high risk polyp

0.97

0.75–0.97

[25,26,27,28]

 Colonoscopy/sigmoidoscopy sensitivity cancer

0.93

0.75–0.95

[25,26,27,28]

 Colonoscopy/sigmoidoscopy specificity

1

N/A

[25,26,27,28]

 Probability of negative sigmoidoscopy and proximal neoplasm

0.21

0.11–0.31

[25,26,27,28]

Complications

 Death from colonoscopic perforation

0.012

0.01–0.02

[30]

 Perforation from diagnostic colonoscopy

0.0008

0.0006–0.005

[30]

QALY

 Local/regional cancer

0.7

0.52–0.9

[31]

 Disseminated cancer

0.25

0.15–0.35

[31]

Costs (US $)

 Cost of colonoscopy

100

30–300

Expert opinion

 Cost of FOBT

8

5–20

Manufacturer price

 Cost of sigmoidoscopy

20

10–100

Expert opinion

 Cost of treating colonoscopic perforation

500

200–1000

Expert opinion

 Cost of local cancer treatment

500

200–1500

Expert opinion

 Cost of regional cancer treatment

9000

500–15,000

[32]

 Cost of disseminated cancer treatment

20,000

5000–25,000

[32]

 Cost of surveillance

200

100–500

Expert opinion