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Table 1 Glossary of model parameters

From: Could CT screening for lung cancer ever be cost effective in the United Kingdom?

  Definition Baseline value & source
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]