Breast cancer is one of the most commonly diagnosed cancer types among women globally. Globally, there were an estimated 2.1 million new cases of breast cancer and 630,000 deaths due to breast cancer in 2018. In the United States alone, there were an estimated 270,000 cases of breast cancer diagnosed in 2018 along with 41,000 deaths, and approximately 1 in 8 women and about 1 in 1,000 men will develop invasive breast cancer at some point in their lives. Thus, the need for effective, lasting breast cancer treatment is urgent.
Increased risk for breast cancer is associated with a personal or family history of the disease and inherited genetic mutations in breast cancer susceptibility genes. These include BRCA1 and BRCA2 and other less common inherited gene mutations. An inherited predisposition to develop breast cancer accounts for approximately 5%-10% of all breast cancer cases, but is rare in the general population (less than 1%). Women with BRCA1 and BRCA2 mutations have an estimated 45% to 65% higher risk of developing breast cancer by age 70, though the risk is highest around age 40. People with these mutations should discuss their risk with a genetic counsellor.
Current methods for breast cancer treatment typically involve surgery if the disease is diagnosed early. Depending on the stage and molecular characteristics of the cancer when diagnosed, breast cancer surgery may be followed by additional chemotherapy, radiation, or targeted therapies, including hormone therapy.
Although breast cancer has long been regarded as difficult to treat with immunotherapy because it is immunologically “cold,” several newer preclinical and clinical studies now suggest that immunotherapy treatment has the potential to improve outcomes for breast cancer patients.
In March 2019, the FDA approved the first checkpoint inhibitor immunotherapy drug, an anti-PD-L1 antibody, in combination with chemotherapy, for the treatment of triple-negative, metastatic breast cancer in patients whose tumors express the PD-L1 protein.
Genetic testing is a type of medical test that identifies changes in chromosomes, genes, or proteins. The results of a genetic test can confirm or rule out a suspected genetic condition or help determine a person’s chance of developing or passing on a genetic disorder.