Screening mammography differs between the United States and the United
Kingdom; a direct comparison may suggest methods to improve the practice.
To compare screening mammography performance between the United States
and the United Kingdom among similar-aged women.
Design, Setting, and Participants
Women aged 50 years or older were identified who underwent 5.5 million
mammograms from January 1, 1996, to December 31, 1999, within 3 large-scale
mammography registries or screening programs: the Breast Cancer Surveillance
Consortium (BCSC, n = 978 591) and National Breast and Cervical Cancer
Early Detection Program (NBCCEDP, n = 613 388) in the United States;
and the National Health Service Breast Screening Program (NHSBSP, n = 3.94
million) in the United Kingdom. A total of 27 612 women were diagnosed
with breast cancer (invasive or ductal carcinoma in situ) within 12 months
of screening among the 3 groups.
Main Outcome Measures
Recall rates (recommendation for further evaluation including diagnostic
imaging, ultrasound, clinical examination, or biopsy) and cancer detection
rates were calculated for first and subsequent mammograms, and within 5-year
Recall rates were approximately twice as high in the United States than
in the United Kingdom for all age groups; however, cancer rates were similar.
Among women aged 50 to 54 years who underwent a first screening mammogram,
14.4% in the BCSC and 12.5% in the NBCCEDP were recalled for further evaluation
vs only 7.6% in the NHSBSP. Cancer detection rates per 1000 mammogram screens
were 5.8, 5.9, and 6.3, in the BCSC, NBCCEDP, and NHSBSP, respectively. Recall
rates were lower for subsequent examinations in all 3 settings but remained
twice as high in the United States. A similar percentage of women underwent
biopsy in each setting, but rates of percutaneous biopsy were lower and open
surgical biopsy higher in the United States. Open surgical biopsies not resulting
in a diagnosis of cancer (negative biopsies) were twice as high in the United
States than in the United Kingdom. Based on a 10-year period of screening
1000 women aged 50 to 59 years, 477, 433, and 175 women in the BCSC, NBCCEDP,
and NHSBSP, respectively, would be recalled; and for women aged 60 to 69 years,
396, 334, and 133 women, respectively. The estimated cancer detection rates
per 1000 women aged 50 to 59 years were 24.5, 23.8, and 19.4, respectively,
and for women aged 60 to 69 years, 31.5, 26.6, and 27.9, respectively.
Recall and negative open surgical biopsy rates are twice as high in
US settings than in the United Kingdom but cancer detection rates are similar.
Efforts to improve US mammographic screening should target lowering the recall
rate without reducing the cancer detection rate.