Table 4. Randomized Controlled Trials of Mammography Among Women Aged 39-74
Studies of Mammography Alone
| Study (reference) |
Ages |
Median followup (years) |
Number of breast cancer deaths/ total number of women (Screened) |
Number of breast cancer deaths/ total number of women (Control) |
Breast cancer death rate per 1,000 women (Screened) |
Breast cancer death rate per 1,000 women (Control) |
Relative risk for breast cancer death (95% Confidence Interval) |
Absolute risk reduction per 1,000 women |
Number needed to invitea |
|
Stockholm23 |
40-64 |
13.8 |
82/39,139 |
50/20,978 |
2.10 |
2.38 |
0.91 (0.65-1.27) |
0.288 |
3,468 |
|
Gothenburg23 |
39-59 |
12.8 |
62/20,724 |
113/29,200 |
2.99 |
3.87 |
0.76 (0.56-1.04) |
0.878 |
1,139 |
|
Malmö23 |
45-70 |
17.1 |
161/21,088 |
198/21,195 |
7.63 |
9.35 |
0.82 (0.67-1.00) |
1.712 |
584 |
|
Swedish Two-County Trial26 |
40-74 |
17 |
319/77,080 |
333/55,985 |
4.14 |
5.95 |
0.68 (0.59-0.80) |
1.809 |
553 |
Studies of Mammography Plus CBE
| Study (reference) |
Ages |
Median followup (years) |
Number of breast cancer deaths/ total number of women (Screened) |
Number of breast cancer deaths/ total number of women (Control) |
Breast cancer death rate per 1,000 women (Screened) |
Breast cancer death rate per 1,000 women (Control) |
Relative risk for breast cancer death (95% Confidence Interval) |
Absolute risk reduction per 1,000 women |
Number needed to invitea |
|
CNBSS-122 |
40-49 |
13 |
105/25,214 |
108/25,216 |
4.16 |
4.28 |
0.97 (0.74-1.27) |
0.12 |
- |
|
CNBSS-220 |
50-59 |
13 |
107/19,711 |
105/19,694 |
5.43 |
5.33 |
1.02 (0.78-1.33) |
-0.097 |
- |
|
HIP19 |
40-64 |
16 |
232/30,239 |
281/30,256 |
5.46 |
6.89 |
0.79 |
1.438 |
883 |
|
Edinburgh18 |
45-64 |
13 |
156/22,926 |
167/21,342 |
6.80 |
7.82 |
0.79 (0.60-1.02) |
1.020 |
980 |
aNumber needed to invite for screening to prevent one death from breast cancer 13-20 years after randomization.
Note: CBE indicates clinical breast examination; CNBSS, Canadian National Breast Screening Study; HIP, Health Insurance Plan of Greater New York.
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