Published on October 7, 2020
What Treatments Are Available For My Type of Triple-Negative Breast Cancer?
Triple-negative breast cancer (TNBC) has various subtypes like patients with the BRCA mutation or metaplastic matrix-forming TNBC. What are the different treatments for each? Tune in as Ricki Fairley and Moira Quinn, both TNBC survivors, talk to Dr. Sara Tolaney of the Dana-Farber Cancer Institute on this important topic.
This is Part 2 of a four-part series. Watch Part 1 (Treatments for Early-Stage Triple-Negative Breast Cancer (TNBC)), Part 3 (Clinical Trials for Triple-Negative Breast Cancer) and Part 4 (Managing the Side Effects of Triple-Negative Breast Cancer) for more information.
This program is supported by an educational grant from Daiichi Sankyo. This organization has no editorial control. It is produced by Patient Power and Patient Power is solely responsible for program content.
Transcript | Triple-Negative Breast Cancer Treatment Options By Subtype
Do TNBC subtypes determine your treatment options?
We can't tell you that one subtype necessarily means one treatment is going to be better than something else and so we don't actually routinely get these subtypes on patients' tumors. It's not like you get a clinical report when you get diagnosed with triple-negative breast cancer that says that you have this specific subtype of disease. The reason is, is that we don't really understand this well enough to use this information clinically at this point in time. I think we will learn more and more as time goes on, but right now it's not something that we're clinically utilizing.
We definitely know lots of things are very unique in a patient's tumor that arises in a patient with an underlying BRCA mutation. These cancers typically are more sensitive to chemotherapy. For example, if you look at patients who get chemotherapy after they're diagnosed with the triple-negative breast cancer prior to going to breast surgery. So, if they get what we call preoperative chemotherapy. And you look at the number of patients who go to surgery and have no cancer left at the time of surgery, that that percentage is higher in someone with an underlying BRCA mutation compared to the average person. Their cancers are much more sensitive to chemo in general.
Are there any preferred treatments for patients with BRCA mutations?
We also have learned that there are certain agents that can work really well in patients who have BRCA mutations. One such example is a class of drugs called PARP inhibitors. Right now these are oral pills that are approved to be used in women who have metastatic triple-negative breast cancer, so cancer that has spread outside the local breast and lymph node area. They were studied in women who had local breast cancers, and we don't have the data from that yet.
There was a trial looking at giving these agents after people had finished their standard treatment for breast cancer and randomized them to get a year of a PARP inhibitor or a placebo to look if that PARP inhibitor changed outcomes for patients with BRCA mutations, and we're waiting on that data, so we don't have it yet. I think in general, the answer to your question is yes. There are some differences in the behaviors of tumors in patients with BRCA mutations compared to none.
How do PARP inhibitors compare with other therapies?
Sure. Would that be an example that’d be carboplatin (Paraplatin)?
That's an excellent question as well. There was initially a lot of work that had been done suggesting that tumors in patients with BRCA mutations may be particularly sensitive to platinum therapy. There was some early work done in patients with BRCA mutations that had shown in patients who got platinum prior to surgery, that the rates of having all their cancer go away with surgery was super high with platinum.
Interestingly, there was a recent presentation done by Dr. Nadine Tung where she actually had done a study in patients with BRCA mutations and they were initially diagnosed with breast cancer and she randomized them to get four cycles of cisplatin (Platinol), so platinum therapy, or four cycles of Doxorubicin (Adriamycin) and cyclophosphamide (Cytoxan). It's a very standard anthracycline treatment that we would give and in fact, people did a little better with the Adriamycin and Cytoxan compared to platinum which kind of surprised us, right? Because there was always this notion that maybe the BRCA patients would do better with platinum compared to the standard Adriamycin drugs but that's actually not the case in this randomized study.
In general, yes, platinum is a great drug for patients with BRCA mutations, but in an early stage patient it is not a replacement for the standard anthracycline therapy.
What is metaplastic triple-negative disease?
Metaplastic triple-negative disease is a subtype of triple-negative breast cancer. It is a rare subtype, so one that isn't super common, but we definitely do see it. In truth, we do treat it like we treat other triple-negative breast cancers that there isn't a distinct treatment for metaplastic cancers compared to a non-metaplastic invasive ductal triple-negative cancer. We would treat them the same, but I will say that there's more and more research that's going on with metaplastic cancers and there does seem to be a sense that metaplastic tumors may be particularly sensitive to immunotherapy.
There is a lot of work being done studying immunotherapy to see how it works in the metaplastic setting, but right now, again, the standard would be the same approach, usually anthracycline and taxane-based chemotherapy.