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

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

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

* Cumulative 15-year development risk for breast cancer for average women, from Figure 1 [28].
^† Cumulative cancer detection rate (CCDR) over 15 years assumes a cumulative sensitivity of 80% from repeated screening.
^‡ Breast cancer screen-free absolute death risk is from Figure 1.
^§ The proportion is the screen-free absolute death risk multiplied by the relative risk reduction (RRR), and then divided by the CCDR.
^∥ Number of cancers needed to be detected (NND) is the reciprocal of the life-saving proportion.
^¶ Assumes maximum prescreening era (1978–1980) 15-year absolute death risk, with no adjustment for improved therapy.

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