If breast cancer cells test negative for estrogen receptors, progesterone receptors, and the HER2 protein, the cancer is called triple-negative. Triple negative breast cancer tends to be more aggressive with a higher chance of systemic recurrence.
How is triple-negative breast cancer diagnosed?
Triple-negative breast cancer is diagnosed after lab tests measuring the presence of hormone receptors (estrogen and progesterone) and HER2 genes and proteins. If cancer cells test negative for all three, this determines that the cancer cells do not depend on estrogen, progesterone, or HER2 to grow.
How is triple-negative breast cancer treated?
Hormonal and targeted therapies are not effective for treating triple-negative breast cancer, because triple-negative cells lack the receptors and proteins that those therapies address. Instead, triple-negative breast cancer is treated with combinations of neo-adjuvant and adjuvant chemotherapy, surgery, and radiation. Surgical treatment is usually a lumpectomy, which removes the cancerous mass; a bilateral mastectomy, which removes all breast tissue that could become cancer, is also an option to prevent recurrence.
Recent studies suggest that triple-negative breast cancer may be a candidate for immunotherapy drugs that have been effective in other kinds of cancer; this still requires more investigation.