A comprehensive review of potential treatment options in the setting of HER2-negative breast cancer.
PUBLISHED April 10, 2019
Kristin E. Fleischmann-Rose, NP: Let’s switch topics and talk about treatment for HER2 [human epidermal growth factor receptor 2]-negative metastatic breast cancer. Nadine, can you discuss how this type of metastatic breast cancer is generally treated? Should patients with hormone receptor-positive disease ever not be considered for hormone therapy?
Nadine M. Tung, M.D.: We’re talking about estrogen receptor-positive/HER2-negative breast cancer, and we’re talking about triple-negative disease. Starting with the estrogen receptor-positive breast cancer, I think it’s usual that we will treat those patients with endocrine therapy, or some people call it hormonal therapy, for as long as the disease responds to that type of therapy: so tamoxifen or aromatase inhibitors, sometimes combined with other therapies like CDK4/6 [cyclin-dependent kinases 4 and 6] inhibitors. But that’s usually the initial therapy. Then when the disease is no longer responding to hormonal therapy, that’s when we would switch to chemotherapy. For triple-negative breast cancer, chemotherapy is really pretty much all that we have. There are some more recent therapies like immune therapies, but the hormonal therapies are not appropriate for those patients. So let me ask you, Kristin, how do you work with physicians and patients to help them achieve their treatment goals in the metastatic setting?
Kristin E. Fleischmann-Rose, NP: You touched on this before. The goal of treatment in the metastatic setting is palliative. So the most important thing that I do when I’m working with patients and providers and their family members is to maximize quality of life. And one of the ways we do that is include medications that lessen disease but also have very few side effects, if at all possible. And then we use appropriate treatment to manage any side effects that patients might have. As I just indicated, the patients are of course part of the treatment team, so these goals and decisions are the result of shared decision making.
Nadine M. Tung, M.D.: And how do you prepare patients for the toxicity or the schedule of the therapy that they’re going to receive in the metastatic setting?
Kristin E. Fleischmann-Rose, NP: We decide on a treatment plan together, and then I schedule a teaching session just with me, the nurse practitioner and the patient. We discuss the medication itself. We discuss the treatment schedule. We discuss the potential adverse events and ways of managing those side effects.
Nadine M. Tung, M.D.: Now we’re going to switch topics and talk about the treatment of metastatic breast cancer in BRCA carriers, meaning patients who’ve inherited an abnormal BRCA gene, BRCA1 or BRCA2, from either of their parents. About 3 percent to 5 percent of all breast cancer patients have inherited an abnormal BRCA gene from one parent, but it’s a larger proportion of some breast cancer populations. For example, about 10 percent to 20 percent of patients with triple-negative disease are BRCA carriers; up to 15 percent of breast cancer patients who are Jewish; and a larger proportion of breast cancer patients if they have a family history of breast cancer, ovarian cancer, or even pancreatic cancer or aggressive metastatic prostate cancer.
For BRCA carriers with breast cancer, the prognosis is the same as if they didn’t have a BRCA mutation, as long as we correct for the type of breast cancers that we talked about and the amount of breast cancer that they have. And in fact, some studies have shown that the breast cancer in BRCA carriers is just as sensitive, if not more, to chemotherapy. It’s actually more sensitive to one particular chemotherapy drug known as platinum, which is not a chemotherapy agent we routinely use in all breast cancer patients.