Breast Cancer Screening Modalities—Beyond Mammography
Monthly breast self-examination (BSE) has been promoted, but there is no solid evidence that it is effective in reducing breast cancer mortality.[11,12] The only large, well-conducted, randomized clinical trial of BSE randomly assigned 266,064 women factory workers in Shanghai to receive either BSE instruction with reinforcement and encouragement, or instruction on the prevention of lower back pain. Neither group received any other breast cancer screening. After 10 to 11 years of follow-up, 135 breast cancer deaths occurred in the instruction group, and 131 cancer deaths occurred in the control group (relative risk [RR] = 1.04; 95% CI, 0.82–1.33). Although the number of invasive breast cancers diagnosed in the two groups was about the same, women in the instruction group had more breast biopsies and more benign lesions diagnosed than did women in the control group.
Other research on BSE is limited. First, Leningrad investigators cluster-randomized more than 100,000 women to BSE training or control. The group that received BSE training had more breast biopsies but no improvements in breast cancer mortality. Second, in the U.K. Trial of Early Detection of Breast Cancer, two districts invited more than 63,500 women aged 45 to 64 years to educational sessions about BSE. After 10 years of follow-up, there was no difference in breast cancer mortality rates compared to those in women from centers without organized BSE education (RR = 1.07; 95% CI, 0.93–1.22). Third, and last, a case-control study nested within the Canadian NBSS compared self-reported BSE frequency before enrollment with breast cancer mortality. Women who examined their breasts visually, used their finger pads for palpation, and used their three middle fingers had a lower breast cancer mortality rates.
The primary role of ultrasound is the diagnostic evaluation of palpable or mammographically identified masses, rather than serving as a primary screening modality. A review of the literature and expert opinion by the European Group for Breast Cancer Screening concluded that "there is little evidence to support the use of ultrasound in population breast cancer screening at any age." In the setting of normal mammography and ultrasonography, less than 3% of women who have a lump will ultimately be found to have breast cancer.[18,19,20,21]