Table 3.

Number of expected clinical events for each screening strategy in the 40-year follow up model

	NBCSP screening	iFOBT every two years	Colonoscopy every 5 years	Colonoscopy every 10 years
CRC cases occurring per 10,000 persons from age 50 to 90 years	6,491	4,745	2,568	4,205
Reduction in CRC incidence compared with NBCSP		27%	60%	35%
CRC by stage
Dukes’ A	3,749	3,513	1,974	3,177
Dukes’ B	1,182	783	380	660
Dukes’ C	424	323	165	289
Dukes’ D	153	126	49	79
Deaths attributable to CRC	983	830	524	722
Reduction in CRC mortality compared with NBCSP		15%	46%	26%
Total Number of colonoscopies	21,333	72,885	167,031	109,213
Number of colonoscopies per life saved		476	363	418

iFOBT₂: immunochemical faecal occult blood test, COLO₅: colonoscopy screening every five years, COLO₁₀: colonoscopy screening every ten years.