A new generation of drugs called targeted therapies are a boon to thousands of women fighting breast cancer. They don’t work for all patients, though. Some breast cancers don’t produce any of the drugs’ three main protein targets, which makes them tough to fight. They’re called “triple-negative” tumors.

Thehang Luu, M.D. (Photo by p.cunningham)

eHope: What is triple-negative breast cancer?

Thehang Luu, M.D.: 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. Those are estrogen receptors, progesterone receptors and human epidermal growth factor receptor 2.

As we learn more about the molecular makeup of human breast cancers, we’re finding that many triple-negative breast cancers — about 85 percent — also fall within a group called basal-like, the most  aggressive form of breast cancer. This is important, because it gives us clues about how to treat them.

EH: How common are these cancers?

TL: Triple-negative breast cancer comprises about 15 percent of all breast cancers. While that is a relatively low percentage, 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.

EH: Are certain women prone to it?

TL: Young African-American women seem to be more likely to have this type of breast cancer. We’re not sure why. Also, women who are positive for BRCA1 mutations [inherited genetic mutations linked to elevated breast cancer risk] are more prone.

EH: How do you treat it?

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

EH: What are researchers doing to improve treatment?
 
TL: We’re learning more about the molecular biology of these cancers. Many of them are basal-like, which means they overproduce other proteins that are potentially promising drug targets. We’re testing the corresponding targeted therapies and drug combinations in hopes those will improve outcomes.

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 should have a better idea of what is effective in the next three to five years.

EH: How can women at risk of this disease or a recurrence protect themselves?

TL: If a woman is positive for BRCA1 mutations, she should speak with her doctor to consider if preventative mastectomy and removal of the ovaries are recommended for her. And a woman with a first-degree relative [parent, sibling or child] who is positive for BRCA mutations should be tested to see if she has 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. 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.