Study: Breast Positioning Significantly Influences Breast Cancer Detection with Mammography (dateline September 13, 2002)
A new study finds that breast positioning is key when detecting breast cancer with mammography. Researchers evaluated several factors including positioning, breast compression, contrast, and exposure, and found that positioning most directly affects the overall image quality, and therefore the detection of breast cancer, on a mammogram. In the study, physicians were significantly more likely to miss breast cancer on a mammogram image if the breast was improperly or poorly positioned during the exam. Experts say the study underscores the need for good communication and cooperation between patients and mammography technologists to help ensure a high-quality mammogram.
Mammography is a special type of x-ray imaging that uses low dose x-rays with high contrast to create detailed images of the breast. Recently, there has been much debate about the benefits of mammography in helping to prevent breast cancer deaths. However, after careful review of research data from the past several years, U.S. government health officials have concluded that mammography is beneficial at intervals of every one to two years for women in their forties and every year for women 50 years of age and older.
The study, led by Dr. Stephen H. Taplin of the Center for Health Studies at the Group Health Cooperative, evaluated the relationship between mammogram image quality among 656 women who had been diagnosed with breast cancer within two years of having a mammogram. In 492 of the cases, breast cancer was first detected by screening mammography while in 164 of the cases, the cancer was detected by other means, such as a physical breast exam.
According to Dr. Taplin and his colleagues, breast cancer was most likely to be detected among the women whose breasts were correctly positioned during mammography. In such cases, 84% of breast cancers were found by screening mammography. However, approximately one-third of the women in the study had poor breast positioning. In these cases, the accuracy of breast cancer detection with mammography dropped to 66.3%. Thus, the researchers conclude that "invasive breast cancer detection by mammography may be improved through attention to correct positioning."
Correct breast positioning during mammography is dependent upon both the mammography technologist and the patient. While the technologist positions each breast in preparation for the mammogram, some women lean back during the exam because the compression of the breast is uncomfortable. According to Dr. Taplin, it is important for women to lean forward during the mammogram so that the maximum amount of breast tissue can be imaged.
In an accompanying editorial in the American Journal of Roentgenology, Stephen A. Feig. MD of the Mount Sinai School of Medicine in New York applauds the study and encourages U.S. radiology practices to concentrate on proper image quality to help increase the number of cancers detected with mammography. Digital mammography, a recent advance in medical imaging, shows potential for helping to improve mammogram image quality.
Because mammography cannot detect 100% of breast cancers, women 40 years of age and older should also receive yearly physician-performed clinical breast exams and practice monthly breast self-exams. Mammography is not usually recommended for women younger than age 40 except in special circumstances; however, these women should still receive physical breast exams and perform monthly breast self-exams.