Table 2

 Time lag to benefit (years) at specific thresholds of absolute risk reduction, for colorectal and breast cancer screening

Absolute risk reduction (95% CI)*
0.00010.00020.00050.0010.002
Colorectal cancer screening (fecal occult blood test)
Minnesota (annual)2.8 (0.5 to 8.7)3.5 (1.0 to 9.1)5.3 (2.2 to 10.5)7.4 (4.0 to 12.6)13.7 (9.5 to 19.0)
Minnesota (biennial)9.9 (3.4 to 24.0)10.4 (2.4 to 22.1)11.6 (6.0 to 20.6)13.3 (8.2 to 20.4)15.6 (11.5 to 20.6)
Nottingham2.2 (0.6 to 5.2)3.3 (1.2 to 7.4)6.1 (2.7 to 11.7)10.4 (5.2 to 18.7)15.7 (11.0 to 21.7)
Funen2.2 (0.4 to 6.7)2.9 (0.7 to 7.9)4.9 (1.8 to 10.8)7.3 (3.8 to 12.6)9.5 (7.6 to 11.7)
Goteborg8.2 (3.0 to 18.8)9.1 (4.1 to 17.7)11.0 (6.4 to 17.8)13.4 (8.9 to 19.2)16.5 (12.7 to 21.0)
Summary3.7 (1.2 to 8.7)4.8 (2.0 to 9.7)7.3 (3.8 to 12.7)10.3 (6.0 to 16.4)14.6 (9.6 to 21.2)
Breast cancer screening (mammography)
Health Insurance Plan-New York2.9 (0.8 to 7.3)3.7 (1.4 to 8.2)5.7 (2.9 to 10.0)7.9 (5.1 to 11.6)9.7 (8.6 to 11.0)
Combined Swedish trials (age 55-64 years)1.0 (0.4 to 2.2)1.9 (0.8 to 3.8)4.3 (2.0 to 8.2)8.9 (4.2 to 16.6)16.2 (11.5 to 22.2)
Combined Swedish trials (age 65-74 years)5.3 (0.4 to 25.7)6.3 (0.9 to 24.2)8.8 (2.4 to 23.7)12.0 (5.1 to 24.4)15.8 (10.5 to 22.8)
Summary1.8 (0.6 to 4.1)3.0 (1.1 to 6.3)6.2 (2.3 to 13.3)10.7 (4.4 to 21.6)15.9 (9.4 to 25.2)

*One death from colorectal or breast cancer prevented per 10 000 people screened (0.0001), per 5000 people screened (0.0002), per 2000 people screened (0.0005), per 1000 people screened (0.001), and per 500 people screened (0.002).