Triple-negative breast cancer is one of the types of breast cancer that can be diagnosed. Its name comes from the fact that the results of three diagnostic tests performed on the cancer cells present in the tissue obtained through tumor biopsy are negative. These three tests detect: estrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2).

About 10% to 15% of all diagnosed breast cancers are triple-negative. Triple-negative breast cancer differs from other types of invasive breast cancer in that it tends to grow and spread more quickly, the treatment options available are more limited, and it is more likely to recur compared to cancers that test positive for these receptors.

How is triple-negative breast cancer diagnosed?

Once a suspicious lesion suggestive of breast cancer has been detected through imaging studies (ultrasound and mammography), your doctor will recommend a breast biopsy to determine the type of cells contained in the lesion.

During the biopsy, a small sample of breast tissue is removed and sent to a laboratory, where a pathologist—specialized in the analysis of blood and body tissues—examines the tissue sample under a microscope and makes a diagnosis.

The pathologist will inform your doctor about the type of cells present in the biopsy. In some cases, the lesion is benign and no cancer cells are found. In other cases, the pathology report indicates that the tissue contains cancer cells (breast cancer).

Cáncer de mama triple negativo Hospital Ruber Internacional Mirasierra

In cases where breast cancer is diagnosed, additional tests are performed to determine whether the cancer cells have certain proteins inside them or on their surface, such as estrogen or progesterone hormone receptors and HER2 protein receptors. Knowing whether the cancer cells contain these receptors helps doctors decide how to treat the breast cancer.

Breast cancers are classified as receptor-positive or receptor-negative depending on whether these receptors are present. If the cells do not have estrogen or progesterone receptors and also do not have HER2 protein receptors above a certain level, the cancer is considered triple-negative breast cancer.