By Teresa Alasio MD
Breast cancer is one of the most common cancers affecting women worldwide, but early detection can save lives. One of the most effective tools in detecting breast cancer early is the screening mammogram, which has played a crucial role in reducing breast cancer mortality rates. However, not all mammograms are the same, and it’s essential to understand the difference between screening mammograms and diagnostic mammograms, as well as when additional tools like breast ultrasound may be necessary.
What is a Screening Mammogram?
A screening mammogram is a routine X-ray of the breasts performed on women who have no symptoms of breast cancer. It is intended to detect early signs of cancer, often before any noticeable lumps or changes in the breast tissue. The American Cancer Society recommends that women with an average risk of breast cancer start receiving annual mammograms at age 40. This screening method is highly effective in identifying breast cancer early, which greatly improves the chances of successful treatment.
The goal of a screening mammogram is to detect cancer early, even before it can be felt. On average, about 4-5 cases of breast cancer are found for every 1,000 screening mammograms performed. Although the vast majority of screening mammograms are normal, a small percentage will show abnormalities that require further investigation.
What is a Diagnostic Mammogram?
If a screening mammogram shows an abnormality or if a woman has symptoms such as a lump, pain, or nipple discharge, a diagnostic mammogram is performed. Unlike screening mammograms, diagnostic mammograms are more detailed and focused on a specific area of concern in the breast. They typically involve additional images from different angles and sometimes involve magnification to get a closer look at the suspicious area. Diagnostic mammograms are critical for clarifying whether an abnormality is benign or malignant.
Breast Density and the Need for Ultrasound
One factor that can make interpreting a mammogram more challenging is dense breast tissue. Dense breasts have less fatty tissue and more glandular and connective tissue, which can make it harder for mammograms to detect abnormalities. In fact, both normal tissue and cancerous tissue can appear white on a mammogram, making it difficult to spot potential tumors in dense breasts.
According to the American College of Radiology, about 40-50% of women aged 40-74 have dense breast tissue. In these cases, an additional imaging test called a breast ultrasound may be recommended to provide further clarity. Ultrasound uses sound waves to produce images of the breast tissue, which can help differentiate between solid masses (which might be cancerous) and fluid-filled cysts (which are usually benign).
Studies have shown that breast ultrasound can detect cancers that may not be visible on a mammogram, particularly in women with dense breasts. For women with dense breast tissue, the addition of breast ultrasound can find an additional 2-3 cancers per 1,000 women screened, a significant increase in detection. This is why it’s often used as a supplemental tool, especially when mammogram results are inconclusive.
The Importance of Early Detection
The key to successful treatment of breast cancer is early detection. When breast cancer is caught early, before it has spread to other parts of the body, the five-year survival rate is over 99%. Screening mammograms, along with follow-up tests like diagnostic mammograms and breast ultrasound when necessary, provide a comprehensive approach to identifying breast cancer at its earliest and most treatable stages.
Women, especially those with dense breast tissue, should be aware of the potential benefits of additional screening methods like ultrasound. Always talk with your healthcare provider about your individual risk factors and the best screening strategy for you.
Screening mammograms remain the first line of defense in detecting breast cancer early, but understanding the role of diagnostic mammograms and breast ultrasound is equally important, especially for women with dense breasts. By staying proactive with regular screening and following up on any recommended additional testing, you’re taking vital steps to protect your health and ensure peace of mind.
The information presented is for education purposes and not meant as a substitute for individual medical advice. If you have a specific medical concern, please see your medical provider.
Dr. Teresa Alasio is the Medical Director and Owner of Intentional Self Aesthetics, located in downtown New Canaan. She happily resides in New Canaan with her family.
