Screening mammography practices differ greatly between the United States and the United Kingdom. (Screening mammography is a type of x-ray designed to find breast lumps that cannot be detected by other means.) In the US, screening is provided in many types of settings, while in the UK, which has a nationalized health system, a single organized screening program provides mammographic screening for virtually all women aged 50 and older. Other differences include the ages at which women are screened, the recommended frequency of screenings, and the number of women who are recalled after their screenings for additional testing and assessment. Recently, a group of researchers compared the performance of these two different screening systems in hopes of finding ways to improve mammographic screening practices in the US.

The results of their study were published in the October 22/29, 2003 issue of the Journal of the American Medical Association. The researchers found that although there was no difference in the detection rates of breast cancer in the two countries, women in the UK were far less likely to be recalled or to undergo negative surgical biopsies (biopsies that did not result in a diagnosis of cancer).

About the study

The researchers compared the recall, surgical biopsy, and cancer detection rates for screening mammography between groups of similarly aged women in the US and the UK. They did this by comparing the mammograms of women aged 50 and over from both countries for a period of three years. Their data was collected from three large-scale mammography screening programs: the Breast Cancer Surveillance Consortium (BCSC) and the National Breast and Cervical Cancer Early Detection Program (NBCCEDP) in the US and the National Health Service Breast Screening Program (NHSBSP) in the UK.

The findings

The study found that the number of women recalled for further assessment in the United States was approximately twice as high as that in the United Kingdom for all age groups. Among women between the ages of 50 to 54 who underwent a first screening mammogram, recall rates were 14.5% and 12.5% in the two US programs and only 7.6% in the UK program.

Despite this higher recall rate, the cancer detection rates for both countries were similar, with rates per 1000 mammograms of 5.8 and 5.9 in the US compared with 6.3 in the UK.

As for biopsy rates, a similar number of women underwent biopsies in both countries. However, physicians in the US conducted more surgical biopsies (in the operating room) and fewer non-surgical needle biopsies (in the office) than in the UK. There were also twice as many negative biopsies in the US than there were in the UK.

How does this affect you?

The study concluded that the recall and negative open surgical biopsy rates were about twice as high in the US than they were in the UK for all age groups. Yet, the rate of cancer detection was similar in both countries. As the goal of any form of cancer screening program is to obtain high rates of detection while avoiding unnecessary diagnostic evaluations, the US could take some lessons from its neighbor across the pond.

Since its inception in 1988, the NHSBSP has worked to integrate quality assurance and feedback mechanisms into all aspects of its program and as a result has seen dramatic improvements in the performance of screening mammography.

Although there are differences between the two countries in the provision and funding of screening mammography, the technology used is quite similar. This means that the United States could conceivably establish similar targets for mammography outcomes and quality assurance without reducing the cancer detection rate.

The results of this study suggest that the US needs to review its current policies and practices surrounding screening mammography. Reducing recall rates and the number of surgical biopsies would have clear benefits for women who would be spared the psychological stress of false-positive results, and for society, which could reduce the economic burden imposed by inefficient mammogram screening programs.

Until such time as new policies and practices are in place, if you are a woman over the age of 50, you may be able to improve the effectiveness and accuracy of your screening mammograms by seeking a facility that employs physicians who read a large number of mammograms and specialize in this field. You should also try to return to the same facility for any and all subsequent mammograms.