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Table 3 Life-saving proportion: women with screen-detected cancers that have their lives saved by mammography.

From: What is the point: will screening mammography save my life?

Age Development risk/1000* CCDR/1000 Death risk/1000 10%
RRR§
15%
RRR
20%
RRR
20%
NND
25%
RRR
30%
RRR
20%
RRR
No Rx
     % % % % % % %
40 31.9 25.5 4.8 1.9 2.8 3.7 27 4.7 5.6 4.7
45 41.9 33.5 6.8 2.0 3.0 4.1 25 5.1 6.1 5.1
50 51.0 40.8 8.8 2.2 3.2 4.3 23 5.4 6.5 5.3
55 59.2 47.3 10.5 2.2 3.3 4.4 23 5.5 6.7 5.2
60 64.4 51.5 11.8 2.3 3.4 4.6 22 5.7 6.9 5.1
65 66.3 53.0 12.7 2.4 3.6 4.8 21 6.0 7.2 5.0
  1. * Cumulative 15-year development risk for breast cancer for average women, from Figure 1 [28].
  2. Cumulative cancer detection rate (CCDR) over 15 years assumes a cumulative sensitivity of 80% from repeated screening.
  3. Breast cancer screen-free absolute death risk is from Figure 1.
  4. § The proportion is the screen-free absolute death risk multiplied by the relative risk reduction (RRR), and then divided by the CCDR.
  5. Number of cancers needed to be detected (NND) is the reciprocal of the life-saving proportion.
  6. Assumes maximum prescreening era (1978–1980) 15-year absolute death risk, with no adjustment for improved therapy.