Promoting Screening Mammography: Insight or Uptake?

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Figure 1.
Estimated breast cancer events per 1000 US women over 10 years at different starting ages, assuming 68% participation in screening mammography. *Data sources are listed in Tables 1 and 2. †At age 50, routine screening saves 1 in 1000 women over 10 years.
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Figure 2.
Estimated single-round screening mammography events and outcomes necessary to save one life by age group. Age-specific events and outcomes per screening round per cancer detected are Breast Cancer Surveillance Consortium data from Ref. 3. *The number needed to detect multiplier and overdiagnosis ratio are derived in Table 2.
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Figure 3.
A: Estimated single-round screening mammograms and follow-up diagnostic events necessary to save one life stratified by age. Age-specific events and outcomes per screening round per cancer detected are Breast Cancer Surveillance Consortium data from Ref. 3. B: Augmented view of estimated screening-induced biopsy outcomes necessary to save one life by age group. DCIS, ductal carcinoma in situ.

Table 1.

Death and Diagnosis Risks Per 1000 Women in the United States over 10 Years

Starting Age (Years)	A (Smoker All-Cause Death Risk)^*	B (Nonsmoker All-Cause Death Risk)^*	C (Breast Cancer Diagnosis Risk)^†	D (DCIS)^† (n [%])	E (Breast Cancer Death Risk, No Screen)^‡	Ratios
						(C−D)/E (Breast Diagnosis to Death Risk)	(A,B)/E (All to Breast Cancer Death Risk, Smoker/Nonsmoker)
40	27	19	18	4 (21)	2.5	6	11/8
50	69	37	30	6 (20)	5.3	5	13/7
60	167	84	42	8 (19)	7.6	5	22/11

* Data in columns A and B are from Ref. 36.
† Column C includes invasive cancer and ductal carcinoma in situ (DCIS) screen detected or not. Column D is DCIS only. Database from Surveillance, Epidemiology, and End Results Program 17 Incidence and Mortality 2000 to 2006.³⁷
‡ Data in column E is from Ref. 13, but uses 10 years instead of 15 and allows for modern therapy but no screening mammography.

Table 2.

Estimated Breast Cancer Events Per 1000 Women in the United States over 10 Years

Starting Age (Years)	F (Lives Saved with Invite to Screening)^*	G (Screen-Detected Cancer)^† (n [%])	H (Pseudo-Disease)^‡ (n [range])	Ratios
				F/G (Life-Saving Proportion [%])	G/F (Number Needed to Detect)	H/F (Overdiagnosis) (n [range])	H/G (Pseudo-Disease) (% [range])
40	0.4	9 (50)	4 (1–6)	4.1	25	11 (2–17)	46 (10–68)
50	0.8^*	17 (55)	7 (1–10)	4.8	21	9 (2–13)	42 (9–62)
60	2.3	23 (56)	10 (2–14)	9.7	10	4 (1–6)	41 (9–61)

* Column F is the absolute risk reduction. The relative risk reductions from an invitation to screening mammography of 15% for women aged 40 to 59 and 30% for women aged 60 to 69 are from Ref. 3 and multiplied by column E, or screen-free absolute death risk. At age 50, routine screening saves 1 in 1000 women over 10 years.
† Column G assumes 74%, 81%, and 82% mammography sensitivity⁴³ and 68% participation in screening from Ref. 3. The product is multiplied by column C.
‡ Column H assumes an overdiagnosis baseline rate of 23%,²⁶ with a range of 5%³ to 34%,²⁷ which are multiplied by column C.