Table 1.

Population Characteristics by Screening Interval for Women With Breast Cancer Who Underwent Screening Mammography Between 1996 and 2011.

	Screening Intervala
Characteristic	Annual	Biennial
Total number of women	12,070	3,370
Screening interval time, median, months	13	24
Age, %
40-49 y	13.6	18.2
50-59 y	29.7	27.4
60-69 y	29.4	25.3
70-85 y	27.3	29.1
Race/ethnicity, %
White, Non-Hispanic	78.4	77.2
Black, Non-Hispanic	4.5	4.5
Hispanic	4.5	5.3
Asian/Pacific Islander	4.9	7.3
American Indian/Alaska Native	0.4	0.7
Other or mixed race	1.1	1.4
Unknown	6.3	3.7
Menopausal Status, %
Premenopausal	12.6	14.9
Postmenopausal without hormone therapy use	42.5	40.1
Postmenopausal with hormone therapy use	21.8	21.0
Surgical menopausal or unknown	23.1	23.9
Type of postmenopausal hormone therapy use at screen, %b
Estrogen + progestogen	46.3	53.8
Estrogen only	53.7	46.2
First-degree family history of breast cancer, %
Yes	23.3	18.3
No	67.4	73.0
Unknown	9.3	8.8
Type of detection, %c
Screen detected (True positive screen)	77.8	72.8
Interval detected (False negative screen)	22.2	27.2

^aAnnual cancers diagnosed within 12 months of screening exam performed 11-14 months after prior mammogram; Biennial cancers diagnosed within 24 months of screening exam performed 23-26 months after prior mammogram.

^bRestricted to 1767 women with known hysterectomy status: women with uterus assumed to use estrogen plus progestogen; without uterus assumed to use estrogen only.

^cScreen-detected breast cancer diagnosed after a positive screening mammography result and interval breast cancer detected after a negative screening mammography result and before the next screening examination.