Most women who undergo biopsies will not have breast cancer. Although some might describe these biopsies as “needless,” in reality they reflect the lack of precision of current detection methods. Some of the imprecision is likely due to the quality of the mammographic interpretation, and some is due to the inherent limitations of the technology. Some solutions to the problem lie in organizational changes, such as adopting different procedures for interpreting mammograms, different standards, and different ways of organizing mammography services. Other solutions might lie in technological improvements.

Screening for breast cancer is organized differently in different countries. A close comparison between the different countries and the results offers some useful insights into strategies for reducing breast cancer mortality in the United States. Mortality is influenced by screening patterns, as well as patterns of care.

Screening programs can be compared according to a variety of measures, such as differences in breast cancer survival rates, rates of abnormal mammograms, or rates of false positives. But there are caveats to each of these measures.

A 2003 study reported that 5-year survival rates for all breast cancers are higher in the United States (89 percent) than in Europe (79 percent), but this was based on data from a heterogeneous group of countries including those with national or regional screening programs (Italy, Spain, The Netherlands, and the United Kingdom) and those without (Estonia and France).101 The study, which compared the United States Surveillance Epidemiology and End Results (SEER) data set with the comparable EUROCARE data set, revealed that breast cancer survival was higher for women in the United States than in Europe, at least for breast cancers diagnosed between 1990 and 1992.a (During the first decade of a service screening program, most breast cancer deaths will occur in women who were diagnosed before the program started which means that a reduction in breast cancer mortality will only emerge when most of the breast cancers in the target population have been screen detected.74) Five-year survival was 89 percent for women in the United States and 79 percent for women in Europe.101 Most of the difference in survival rates was due to the stage at which women were diagnosed. Forty percent of tumors in the SEER data set were early stage (T1N0M0) compared with only 30 percent in the EUROCARE set.b The authors attribute these differences to the availability

a  

Analyses of breast cancer survival outcomes do not reflect recent practice changes, either in detection or treatment, because of the need to use a study period that is at least as long as the natural course of the disease, which is about 10 years.

b  

T1 indicates a tumor less than 2 cm, N0 indicates that the cancer has not spread to the lymph nodes, and M0 indicates the absence of metastasis to other organs.



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