Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
APPENDIX B 135 new disease in this population may be relatively low and thus the effectiveness of screening may be limited, but reliable data are lacking. Although no large study has quantitated the effectiveness of breast cancer screening for women in high-risk groups, it is apparent that these women have a greater probability of developing the disease.30 If screening can reduce the risk of mortality from breast cancer, there may be a greater effect from screening those in high risk groups, but studies confirming this effect are lacking. Further, established risk factors are present in less than one-quarter of women with breast cancer, so that a screening program restricted to high-risk groups is likely to miss the majority of cases. Retrospective studies of the effectiveness of BSE have produced mixed results, and BSE has not been studied in a prospective controlled trial with mortality as an outcome.8 A recent meta-analysis of pooled data from 12 studies found that women who practiced BSE before their illness were less likely to have a tumor of 2.0 cm or more in diameter or to have evidence of extension to lymph nodes.36 The studies from which these data were obtained, however, suffer from important design limitations and provide little information on clinical outcome (e.g., breast cancer mortality). Recommendations of Others The American Cancer Society37 and the National Cancer Institute38 recommend monthly BSE and regular clinical examination of the breast for all women; baseline mammography between ages 35 and 40, followed by annual or biennial mammograms from ages 40-49; and annual mammograms beginning at age 50. These recommendations have been supported by other groups such as the American Medical Association,39 the American College of Obstetricians and Gynecologists,40 and the American College of Radiology.41 A joint statement on screening for breast cancer involving many of these organizations is currently being developed under the organization of the American College of Radiology.42 In contrast, the Canadian Task Force,43 American College of Physicians, 44 and other authorities45,46 support annual clinical breast examinations for all women starting at age 40 but do not recommend beginning yearly mammography until age 50. The World Health Organization states that there is insufficient evidence that BSE is effective in reducing mortality from breast cancer.47 Thus, it does not recommend BSE screening programs as public health policy, although it finds equally insufficient evidence to change such programs where they already exist.