Table 6. Application of parameters in current model to figures of Atkin et al, 1993.

Parameter	Atkin et al	Geurts et al	Correction factor (ratio)	Application of Geurts et al's assumptions to the Atkin et al's estimates
Annual reduction in CRC deaths of FS vs no screening (based on data from 1987)	3499
Eligible population size	602400 persons aged 58 in the UK in 1987	On average 501 000 persons aged 55 in England in 2013–2030 (Table 3)	0.83	2910
Age at FS	58 years	55 years (20-year mortality rate 20% lower, CRUK)	0.80	2328
Case fatality rate	60%	38%	0.63	1474
Effect size	HRR CRC mortality FS vs no screening=0.67	HRR CRC mortality FS vs no screening=0.69 (UK FS trial, Table 1)	0.94	1385
Uptake FS	70%	50%	0.71	989
Number of age cohorts	22 (age 57–79)	17 (age 55–72)	0.77	764
Net benefit after partial coverage by gFOBT	Not applicable	HRR FS vs no screening=0.78; HRR FS plus gFOBT vs gFOBT=0.70/0.87=0.80 (for gFOBT screening years)	0.91	695
Annual reduction in CRC deaths of FS plus gFOBT vs gFOBT in 2030	695	349

Abbreviations: CRUK=cancer research UK; FS=flexible sigmoidoscopy; gFOBT=guaiac faecal occult blood test; HRR=hazard rate ratio.