Breast Cancer
HER2-Positive mBC
Breast cancer is the most common cancer in women in the U.S., and HER2-positive breast cancer accounts for about 20 percent of all breast cancer diagnoses (in 2023, that’s 297,790 women and 2,800 men who will be diagnosed). HER2-low breast cancers, which express low levels of HER2, represent an additional 55 percent of all breast cancer cases.
HER2-positive breast cancer is aggressive and fast-growing and was previously associated with poor outcomes and higher mortality rates than other breast cancer subtypes. With the development of HER2-targeted agents, HER2-positive breast cancer is now a treatable disease and outcomes have dramatically improved for these patients.
Currently, survival rates exceed 90 percent in HER2-positive breast cancer that is diagnosed early and treated with chemotherapy and dual antibody therapy. However, five-year survival rates vary by hormone receptor (HR) status and differ based on the location of the cancer at diagnosis, with better outcomes observed for localized (confined to the breast) compared to regional (near the breast) or distant (metastatic) HER2-positive breast cancer.
Certain standard chemotherapy drugs also can be effective in treating HER2-positive breast cancers, although these drugs don't specifically target the HER2 protein.
Experts recommend that every invasive breast cancer be tested for the presence of HER2 because the results significantly impact treatment recommendations and decisions. HER2 testing is not done routinely for ductal carcinoma in situ, except as part of a clinical trial.
Whenever breast cancer recurs or spreads, the cancer cells should be retested for HER2 as well as for hormone receptor status, as these can change from the original diagnosis.
On this site, we invite you to explore more about breast cancer, specifically about HER2 Positive mBC. Our goal is to provide you with a better understanding on this cancer, the epidemiology and pathophysiology surrounding the disease, and selecting treatment. We have also provided a patient toolkit specifically for patients that addresses topics such as living with cancer, frequently asked questions, and caregiver support to help patients better understand this type of cancer. Thank you for visiting!
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