Triple negative breast cancer is a subtype of breast cancer that lacks three receptors known to fuel most breast cancers: estrogen receptors, progesterone receptors or human epidermal growth factor receptor 2 (HER2). 15% of women will be diagnosed with this type of breast cancer. Among younger women with breast cancer, up to 1 in 5 will be diagnosed with triple negative breast cancer. Triple negative breast cancer is also the most common type of breast cancer diagnosed in women who carry an altered BRCA1 gene, which increases their likelihood of being diagnosed with breast cancer. Extensive research has taught doctors that triple negative breast cancer behaves aggressively and, without treatment, has a high chance of spreading or metastasizing. Because of the risk this type of breast cancer poses, doctors are continuing to learn more about it in order to find better treatments.
For decades, doctors have relied on chemotherapy as the only option to treat triple negative breast cancers. Though triple negative breast cancer is an aggressive form, it is also the type of breast cancer that is most likely to benefit from chemotherapy. Certain chemotherapies or combinations of chemotherapy appear to be effective in treating triple negative breast cancer and ongoing studies are looking at new combinations of these drugs specifically in triple negative tumors, both in the advanced and early stage.
However, chemotherapy alone is not sufficient. Scientific research has identified a large number of other pathways that breast cancer cells use to sustain themselves and eventually spread. Identifying these pathways shows promise for treating triple negative breast cancer and clinical trials are now ongoing that are specific for women with triple negative breast cancer.
Most recently, significant results have been seen with the PARP inhibitors. These drugs work by blocking enzymes in cancer cells that help them repair their own damaged DNA. When cancer cells cannot repair their DNA after treatment, the cells eventually die. This mechanism appears to be especially important for BRCA gene altered cancers and triple negative cancers. In combination with chemotherapy, the PARP inhibitors significantly improved responses for women with advanced breast cancer. Several different types of PARP inhibitors are now being studied specifically for triple negative cancers, either as single drug therapy or in combination with other standard forms of chemotherapy. Go here to find more information about these trials.
Given the aggressive nature of triple negative breast cancers, it is important that you discuss treatment options with your doctor and consider participating in a clinical trial, if possible.
If you’d like to learn more about triple-negative breast cancer, pick up a copy of our Guide to Understanding Triple-Negative Breast Cancer, created in partnership with the Triple Negative Breast Cancer Foundation. You can download a PDF online, order from our Marketplace or call us at (610) 645-4567.
As always, if you have something to say, leave us a comment! Or start a discussion on Facebook.
This entry was written by Virginia F. Borges, MD, MMSc. Dr. Borges is an assistant professor of medicine at the University of Colorado Health Science Center. She is also a member of our medical advisory board.