You’re a conscientious woman. You value your health and want to make sure you are actively pursuing optimum wellness. You know that breast cancer is common, and you know that it is treatable if it can be diagnosed in its early stage. So you get your screening mammogram, and ... it’s abnormal.
Your doctor has written an order for you to have a diagnostic mammogram, breast ultrasound, and a biopsy if it’s needed. Anxiety marches in, along with questions: What is a diagnostic mammogram? Why do I need an ultrasound? Biopsy: what? Don’t only people with cancer need biopsies? Wait, do I have cancer?
To answer these questions, it is important to first understand the screening mammogram. The screening mammogram is a formulaic set of images, designed to give the most information about the breast tissues in the smallest number of pictures. A screening mammogram includes four to eight standard images, and is basically a bird’s eye view of what’s going on in the breasts. If there is any hint of change since the previous mammogram, the screening study is deemed incomplete, and a diagnostic breast imaging workup is recommended. On average, about 1 in 10 women will be recalled from the screening mammogram for a diagnostic exam. The likelihood of needing a diagnostic exam is increased if the screening study is your first mammogram, or if you haven’t had a mammogram in many years.
Unlike the screening exam, the diagnostic breast imaging workup is an individualized, highly tailored exam that typically starts with additional mammographic pictures. These pictures could include spot compression views in which a special type of mammogram paddle is used to smooth out the breast tissues in a small area, in the region of concern. Magnification views are another kind of technique used in the diagnostic setting to characterize findings with maximum detail. A breast imaging radiologist physician interprets these diagnostic mammogram views immediately after they are performed, and determines the next steps in the evaluation.
Not always but very often, a breast ultrasound is recommended by the radiologist following completion of the mammogram portion of the diagnostic breast imaging evaluation. Breast ultrasound is a powerful adjunct to the mammogram because it gives complementary information about the composition of the breast tissues. It helps characterize masses as solid or cystic, and provides another layer of detail regarding the way each individual woman’s breast tissues are organized. Most diagnostic breast imaging exams are complete after the customized mammography and ultrasound images are performed, but occasionally your breast imaging radiologist may recommend an MRI as a supplemental study that gives powerful information about how the breast tissues are behaving.
It is a common misconception that most diagnostic breast imaging exams result in a recommendation for tissue sampling (aka biopsy), and a subsequent cancer diagnosis. But nationwide statistics reveal that only about 17% of women are recommended for biopsy based on the diagnostic exam. So the great majority of diagnostic breast imaging evaluations end up being assessed as negative or likely benign. When a breast biopsy is needed, women may be comforted to know that breast imaging physicians are obliged to biopsy any finding that has a greater than 2% risk of malignancy based on its appearance. This means the radiologist must be greater than 98% certain that cancer is not present in order to avoid biopsy – a very high standard to meet. Of those women recommended for biopsy, statistically about 30% will be diagnosed with breast cancer, and approximately 70% of breast biopsies will be negative for cancer.
In summary, an abnormal screening mammogram is not a definite cancer diagnosis. But a more personalized evaluation is necessary to ensure your optimal health and exclude the presence of an early, potentially curable breast cancer.