What is triple-negative breast cancer?

Triple-negative breast cancers are those that do not have any of the three major types of proteins that some of our current therapeutic drugs target. These proteins are estrogen receptors, progesterone receptors and human epidermal growth factor receptor 2. Since these breast cancers don’t produce any of the three main proteins that targeted therapies aim for, it can make them tough to fight.

Triple negative breast cancer is relatively uncommon and comprises about 15 percent of all breast cancers. However, it’s important to note that about two-thirds of those are high-grade (grade 3) at diagnosis, compared to less than one-third of other breast cancers. Being high-grade means they’re aggressive and likely to recur, usually within one to three years.

Young African-American women seem to be more likely to have this type of breast cancer. Also, women who are positive for BRCA1 mutations [inherited genetic mutations linked to elevated breast cancer risk] are more prone.

Initially, especially if we catch it early, we treat triple negative breast cancer like any other, with combined surgery, chemotherapy and radiation therapy where appropriate. For advanced or recurring tumors, we rely mostly on chemotherapy.

Researchers are working hard to test new therapies and drug combinations that will improve outcomes in patients with triple negative tumors. We’re finding that many triple-negative breast cancers — about 85 percent — also fall within a group called basal-like, which means they overproduce other proteins that are potentially promising drug targets. Currently, some researchers are testing drugs called PARP inhibitors. These block a cancer cell’s ability to repair DNA damage caused by chemo- and radiation therapies and could make those treatments more effective. We’re also looking at anti-angiogenesis drugs. These block the formation of new blood vessels that feed tumors. We hope to have a better idea of what is effective in the next three to five years.

At-risk women, such as those positive for BRCA1 mutations, should speak with their doctor to consider if preventive mastectomy and removal of ovary are recommended. Women with a first-degree relative [parent, sibling or child] who is positive for BRCA mutations should be tested to see if they have the mutations, as well.

For the average woman, recent research confirms that the common-sense advice of eating right and staying fit is the most effective strategy to protect themselves. It not only can reduce risk of breast cancer, but it can increase the odds of a good outcome for patients who already have the disease or are facing the possibility of recurrence. That’s particularly important for triple-negative breast cancers, where recurrence is more likely than with other types.