Table 1 Glossary of model parameters

A

Age – sub-scripted CT (age at CT screening) and SP (age at symptomatic presentation)

B

Health benefit gained as a result of early detection, per cancer

1.7 QALYs – determined by the survival model

C

Probability of an individual of screening age surviving until symptomatic presentation

0.88 – UK Life Tables [38]

E

Lead time (years between detection at screening and symptomatic presentation)

8 years – [44, 45]

G _CT

Gross costs of screen-detecting and treating a case of lung cancer

£12,000 – [26, 27]

G _SP

Gross costs of diagnosing and treating a cancer presenting symptomatically

£7,050 – [26, 27, 29, 30]

I

Cost of investigating a positive resulting from the initial screening test

£503 – Cost of bronchoscopy [23]

M _A

Mortality rate at age A

N

Numbers of individuals in a cohort – sub-scripted CT (screening) and SP (symptomatic presentation)

P

Prevalence of lung cancer in the population targeted for screening

1% – average of [34-36]

R

Discount rate

3 1/2% – [46]

S

Unit cost of the initial screening test (CT scan).

£60 – [23]; includes £4 allowance for administration

T

The net additional cost of treating a screen-detected cancer, as opposed to one presenting symptomatically

£7,286 – calculated from C, E, G _CT , G _SP and R

X

Sensitivity of the screening test

85% – [11, 14, 31]

Y

Specificity of the screening test

85% – [11, 31, 32]