Case-control studies, nonrandomized trials, and cohort evidence about the effectiveness of BSE is mixed; results are difficult to interpret because of selection and recall biases. For example, a small case-control study in Seattle, Washington, compared self-reported practice of BSE in women with advanced breast cancer with that in age-matched controls. The frequency of practicing BSE did not differ in these groups, and there was no decrease in the risk of advanced-stage breast cancer associated with BSE (RR = 1.15; 95% CI, 0.73-1.81). BSE proficiency was low in both groups of women.
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 mortality rates in these two districts compared with four centers without organized BSE education (RR = 1.07; 95% CI, 0.93-1.22).
A case-control study nested within the Canadian NBSS suggests that well-performed BSE may be effective. This study compared self-reported BSE frequency before enrollment in the trial 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.
A device called the Sensor Pad was designed to improve the accuracy of BSE and has been approved by the FDA; however, there is no evidence on its efficacy to decrease breast cancer mortality.
The primary role of ultrasound is the evaluation of palpable or mammographically identified masses. 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.
Magnetic Resonance Imaging
There is increasing interest in using breast magnetic resonance imaging (MRI) as a screening test for breast cancer among women at elevated risk of breast cancer based on BRCA1/2 mutation carriers, a strong family history of breast cancer, or several genetic syndromes such as Li-Fraumeni or Cowden disease.[73,74] Breast MRI is a more sensitive modality for breast cancer detection as compared with screening mammography, but it is also less specific.[75,76]
Direct back-to-back comparisons of breast MRI and mammography in young high-risk women report MRI sensitivities ranging from 71% to 100% versus mammography sensitivities of 20% to 50%. The low sensitivities of mammography are consistent with previous experience in young women and those with dense breasts. Contrast-enhancing foci are normal in healthy breasts, and false-positive results are common.[77,78] These same studies show that MRI is also associated with threefold to fivefold higher recall rates, higher false-positive rates (with specificities varying from 37%-97%), and substantially worse PPVs. Thus, women who are screened with MRI have more negative surgical biopsies.