Does This Patient Have Breast Cancer? The Screening Clinical Breast Examination: Should It Be Done? How?

Abstract

The authors conducted an extensive search of the literature and investigation of many published studies to collect information on the optimal use of clinical breast examinations (CBEs). All published clinical screening programs that used CBEs as part of the screening process were analyzed to determine the effectiveness of clinical examinations in screening for breast cancer. There were no published reports of screening with CBEs alone. Studies that investigated the use of silicone breast models, as well as those of actual clinical techniques, were included in the investigation of optimal CBE methods. A meta-analyses of studies found that, in women aged 50 to 69 years, screening with either CBE, mammography, or both methods reduces deaths due to breast cancer by one-fourth. For women in their 40s, deaths were reduced by 18 percent. In the Canadian study, women in their 50s were screened yearly for 5 years with either yearly mammography and CBE or CBE only. Over a 7-year period, deaths due to breast cancer were similar in the two groups. The Health Insurance Plan study, which found CBE to be superior to early forms of mammography at detecting breast tumors, was conducted in the 1960s when mammography techniques and interpretation were not well developed. Mammography seems to be more sensitive than CBE alone, but the greatest sensitivity is achieved when both methods are used (Table 1). No evidence could be found in these studies that screening with both CBE and mammography ultimately reduces the rate of death due to breast cancer more than mammography alone. Women whose cancer was found by breast examination but missed by mammography had a higher mortality rate than women whose cancers were detected by mammography. In these studies, CBE had a high false-positive rate and a higher false-negative rate for detecting breast cancers. The overall sensitivity for CBE was 54 percent. Specificity was 94 percent. Table 1: Proportion of cancers detected by clinical breast examination (CBE) and mammography screeningThe studies did show, however, that sensitivity increased with the length of the breast examination. Examiners who spent the most time on examinations consistently had the highest sensitivity rates. In the Canadian National Breast Screening Study, examiners who spent between 5 and 10 minutes on the complete examination achieved a sensitivity of 69 percent. Only one investigation made any attempt to use a standard method for the CBE, and other studies indicated that the findings of clinicians using nonstandardized breast examination methods agree only slightly better than chance. The technique used had an impact on the sensitivity of the examination. When a thorough, systematic search pattern with varying palpation pressures, using the pads of three fingers in a circular motion, was used to examine silicone models, sensitivity increased. Experience and training increased the effectiveness of the examiner. In tests with silicone models, residents were better than untrained lay women at finding suspicious lumps. With training, the women improved almost to the level of the residents, and with experience, the sensitivity of the residents further increased. There was little information in the studies to support recommendations for careful visual inspection of the breast in various positions. Visual inspection while performing the examination seemed to be sufficient. Nor was there any evidence that squeezing the nipple to check for discharge was valuable in detecting breast tumors. In women with otherwise normal findings, spontaneous discharge was associated with the presence of breast tumor in only 2 percent of patients. There was no cancer found in women with expressed discharge. JAMA 1999;282:1270–1280