The clinical breast examination (CBE) is often used to screen for breast cancer. Barton and colleagues review the evidence of the effectiveness of this examination.
A woman who has more risk factors for breast cancer and who has an abnormal CBE has a higher likelihood of having breast cancer than a woman who has fewer risk factors. For example, the predictive value of a positive clinical test is higher in older women than in younger women. A literature review was conducted to determine the effectiveness and methods of performing CBE. Unfortunately, no studies compare CBE to no CBE, so determining effectiveness is difficult. Some studies compare CBE to CBE plus mammography and, in these, women screened with both techniques had mortality rates similar to those in women who only had CBE. This result might mean that mammography may not offer advantages over screening CBE. However, the sensitivity of mammography was generally found to be superior to that of CBE. Overall, it is difficult to determine what part CBE plays in reducing breast cancer mortality in women who are screened with CBE or CBE plus mammography.
There is not really any gold standard to compare CBE with, but a compromise criterion is to follow all women screened, obtain histologic proof in women who are diagnosed with breast cancer and determine the rate of breast cancer in these screened women. Using these standards, sensitivity of CBE was determined to be about 54 percent, and specificity was approximately 94 percent.
Examiner factors also play a role in determining the accuracy of CBE. Among these are duration of examination, examination technique and examiner experience. One study determined that the highest sensitivity occurred when the examiner spent between five and 10 minutes performing the examination. The technique most likely to improve the sensitivity of the examination (see accompanying figure on page 1471)
involved a systematic pattern with varying palpation pressures. If it is decided that a CBE is warranted, all breast tissue (from the axilla to the clavicle to the midsternal line to the brassiere line) should be examined; a “lawnmower” technique is recommended as being more thorough than a radial spoke pattern or concentric circles. A thorough examination for a woman with an average brassiere size (B cup) should take at least six minutes.
The authors conclude that women at risk for breast cancer should have screening CBEs. Although the results of their review are not conclusive, it seems that mortality rates may be reduced in women who are so screened. Proper technique, including duration of examination, is crucial.
editor's note: The U.S. Preventive Services Task Force gives the CBE a “C” rating, meaning that there are insufficient grounds to recommend for or against the examination. Some have advocated encouraging increased patient awareness of changes in the breast (rather than breast self-examination per se) with the goal of increasing contact with physicians, so that mammogram rates may be improved. When a CBE is performed, the authors are correct in encouraging a thorough examination of adequate duration to detect potentially curable breast cancers.—g.b.h.