After skin cancer, breast cancer is the most common cancer that women are diagnosed with in the United States. Increases in both awareness and funding have helped provide opportunities for advancements in the diagnosis and treatment of breast cancer. The number of deaths attributed to breast cancer have decreased over the years, largely due to methods like early detection.
Breast cancer is sometimes found after symptoms appear, but oftentimes women with breast cancer experience no symptoms. Due to this possibility of remaining asymptomatic for years, regular breast cancer screenings are vital.
Screening refers to exams used to find a disease in individuals who aren’t yet experiencing symptoms. Early detection allows for the discovery, diagnosis and treatment of a disease earlier than if an individual were to wait for symptoms to present. Breast cancers found during screening exams are more likely to be smaller and still confined to the breast. The size of a breast tumor and how far it has spread are some of the most important factors in predicting the outcome of a woman with this disease. Women for whom breast cancer is detected at an early stage have a 93% or higher survival rate in the first five years.
While detection has been made easier by new and improved methods, risk factors still play a crucial role in determining the results of screenings as well as health outcomes. The sex and age of the individual play a major role, with the majority of breast cancers being found in women who are 50 years or older. Additional factors such as genetic mutations, dense breast tissue, and family history of cancer can also play a role in increasing a person’s risk of breast cancer. However, some women will get breast cancer even without any known risk factors. Similarly, having a risk factor does not guarantee that someone will get the disease, and not all risk factors have the same effect. Nearly all women have some combination of risk factors, but most do not get breast cancer. While some risk factors are inevitable, some can be controlled including frequency of physical activity, use of hormone supplements, reproductive history, and alcohol use. In regards to screening, an important risk factor to consider is the density of breast tissue.
Breast density is the ratio of dense tissue, such as connective and glandular tissue, in a woman’s breasts compared to fatty tissue. According to the CDC, breast density can fall within one of the following four categories: “the breasts are almost entirely fatty (about 10% of women), a few areas of dense tissue are scattered through the breasts (about 40% of women), the breasts are evenly dense throughout (about 40% of women), and the breasts are extremely dense (about 10% of women).”
Not all women with dense breast tissue have a high risk of breast cancer, but this does contribute to an increased risk. Breast density is important to consider when thinking about breast health and a breast cancer screening plan.
One of the most popular screening methods is the mammogram, which is an X-ray picture of the breast. Regular mammograms are among the most effective tests doctors have to find breast cancer early, allowing for detection up to three years before a tumor can be felt.
Breast magnetic resonance imaging (MRI) is another method of screening that is often used in conjunction with mammograms. A breast MRI captures multiple images of the breast which, when combined, are able to create a more detailed picture of the breast tissue. This procedure is usually done following a biopsy that is positive for cancer, but it can also serve as a precautionary method for certain groups that are at higher risk of breast cancer. This includes women who have a very strong family history of cancer or carry a hereditary breast cancer gene mutation. Mammography screening has been shown to be the most reliable exam as it has data to support the reduction in deaths due to breast cancer.
While the mammogram is one of the best methods for screening, another route is a breast ultrasound, an imaging test that uses sound waves to look at the inside of the breasts. The main focus of this test is to look at blood flow to the breasts. This test is normally a follow-up procedure for when a change has been detected with a mammogram or when a change is felt, but does not show up on a mammogram. The device used allows the doctor to hear how fast blood is flowing through a blood vessel and in which direction it is flowing. If there is no sound or a faint sound, there may be a blockage in the flow, which could be indicative of a tumor.
While this technique is not the traditional choice for breast cancer screening, it can be useful for women with more dense breast tissue as a mammogram may have limited visibility. Additionally, for women who are pregnant or under the age of 25, ultrasounds may serve as a better alternative to mammograms as it does not use radiation.
Still, this method has certain limitations for women with very dense breast tissue. For these women, another screening option is the Abbreviated Breast MRI (AB-MRI). The main difference between an AB-MRI and a regular MRI exam is the procedural time. In an AB-MRI, only the most important sequences for detecting breast cancer are performed, and the test is completed within 10-15 minutes. This method has been shown to be as sensitive as a traditional MRI, but at a reduced cost to the patient.
A study was done on the first clinical implementation of the AB-MRI as a supplemental screening test for breast cancer. The results demonstrated an increase in cancer detection with greater prediction ability than mammograms. The study did note that more data needed to be collected from sites with diverse screening populations to ensure generalizability.
While there is no one perfect method for detecting breast cancer, the options for women continue to grow and become more readily available. For women with dense breast tissue, the AB-MRI is one of the many advancements that have been made to increase the sensitivity of breast cancer detection.