Table 1

Relative risk of breast cancer death before screening start in women likely and not likely to participate in screening, and relative risk of breast cancer death after a period of screening with 75% participation.

Before screening

After years of screening

Correction according to Duffy et al. (2002) [18]


BC death ratea

Change in mortality due to screening

Change in mortality unrelated to screening

BC death ratea

Dr

A = p × RR × Dr

B = 1-[(1-p) × Dr]

Corrected RR (= A/B)


Panel A

Participants

86

0%

0%

86

Non-participants

142

0%

0%

142

All womenb

100

0%

0%

100

RR breast cancer death, participants versus non-participants

0.61

0.61

1.42

0.65

0.65

1.00

Panel B

Participants

86

-20%

0%

69

Non-participants

142

0%

0%

142

All womenb

100

-15%

0%

85

RR breast cancer death, participants versus non-participants

0.61

0.48

1.42

0.52

0.65

0.80

Panel C

Participants

86

0%

-25%

65

Non-participants

142

0%

-25%

107

All womenb

100

0%

-25%

75

RR breast cancer death, participants versus non-participants

0.61

0.61

1.07

0.48

0.73

0.66

Panel D

Participants

86

-20%

-25%

47

Non-participants

142

0%

-25%

107

All womenb

100

-15%

-25%

60

RR breast cancer death, participants versus non-participants

0.61

0.44

1.07

0.35

0.73

0.48


BC: Breast cancer; Dr: rate in non-participants after screening divided by the rate in all women before screening; p: participation rate of 75%; RR: relative risk. aPer 100,000 women-year. b(rate in participants × 0.75) + (rate in non-participants × 0.25).

Autier and Boniol BMC Medicine 2012 10:163   doi:10.1186/1741-7015-10-163

Open Data