Media coverage surrounding the article on breast self-examination by the Canadian Task Force on Preventive Health Care1 drew strong reactions from women who felt disempowered by its recommendations or who were incredulous at the conclusion that not only is breast self-examination of no use but it may result in psychological harm and unnecessary costs. Their distress should give us pause for reflection.
Breast self-examination is not a preventive measure: it cannot prevent cancer. Rather, it is a diagnostic technique and should be evaluated as such.2 The accepted method to evaluate diagnostic measures is to assess sensitivity and specificity relative to some gold standard. If the performance of the evaluated technique is adequate, the decision to use one approach over another can then be based on factors such as acceptability to the patient and cost–benefit ratio. Rather than focusing on whether breast self-examination can reduce mortality, the authors should have focused on whether it is a reasonable alternative to clinical breast examinations or mammography or both at various stages of a woman's life. A recent Canadian study suggested that mammography provided no additional benefit in a group of women who performed breast self-examination.3
There are a number of issues related to the systematic review process that are of concern in this report, such as the use of one reviewer throughout the process.4 Our most serious concern is that this systematic review was conducted using techniques that are suitable for studies of prevention or treatment. The resulting recommendations are potentially erroneous.
Signatures
Tammy J. Clifford
Thomas C. Chalmers Centre for Systematic Reviews Children's Hospital of Eastern Ontario Research Institute Ottawa, Ont.
Margaret Sampson
Thomas C. Chalmers Centre for Systematic Reviews Children's Hospital of Eastern Ontario Research Institute Ottawa, Ont.
Howard M. Schachter
Thomas C. Chalmers Centre for Systematic Reviews Children's Hospital of Eastern Ontario Research Institute Ottawa, Ont.
References
- 1.Baxter N, with the Canadian Task Force on Preventive Health Care. Preventive health care, 2001 update: Should women be routinely taught breast self-examination to screen for breast cancer? CMAJ 2001;164(13):1837-46. [PMC free article] [PubMed]
- 2.Irwig L, Tosteson ANA, Gatsonis C, Lau J, Colditz G, Chalmers TC, et al. Guidelines for meta-analyses evaluating diagnostic tests. Ann Intern Med 1994;120(8):667-76. [DOI] [PubMed]
- 3.Miller AB, To T, Barnes CJ, Wall C. Canadian National Breast Cancer Screening Study — 2: 13-year results of a randomized trial in women aged 50–59 years. J Natl Cancer Inst 2000; 92 (18): 1490-9. [DOI] [PubMed]
- 4.NHS Centre for Reviews and Dissemination. Undertaking systematic reviews of research on effectiveness: CRD guidelines for those carrying out or commissioning reviews. 2nd ed. York (UK): University of York; 2001. Report no.: 4.