Role of Chemotherapy for Breast Cancer

In this video, we discuss the two roles for chemotherapy in breast cancer in simple terms - up front as part of a curative treatment, and for metastatic disease that has spread from the breast to other organs.

Read the full video transcript below:

Chemotherapy for breast cancer is used in two main settings.

First, upfront as part of a curative treatment for non-metastatic cancer, either before surgery or after surgery. The second use for chemotherapy is in the metastatic setting, once a tumor has left the breast and has gotten into other organs in the body. 

To be clear, not all patients develop metastases, and therefore not all patients who get chemotherapy experience it in both of these scenarios. The idea is to use chemotherapy upfront to prevent the second metastatic scenario from ever happening.

To illustrate the use of chemotherapy as part of a curative upfront treatment, let's look at a woman who has a large tumor in the breast. 

It's large enough that its removal immediately would require probably a mastectomy because it's too big for a lumpectomy to leave a reasonably good cosmetic result. Chemotherapy is started before surgery, and the tumor shrinks. Sometimes this allows for a lumpectomy instead of a mastectomy, but it also gives a good trial of chemotherapy to see how that tumor responds to treatment in that patient. This can be very useful if the patient needs additional chemotherapy down the road. 

Some women go straight to surgery and don't have chemotherapy before. They have chemotherapy after surgery. The purpose of treatment in this scenario is to destroy any microscopic circulating small amounts of cancer cells that could be circulating through the bloodstream to destroy them before they ever lodge in a different organ and become a site of distant metastatic disease in the future.

To be clear, when chemotherapy is used in this situation, we don't have any evidence that there's metastatic disease, but we have developed more sophisticated tools for finding women who are at high risk for developing metastatic disease in the future.

Now let's shift our focus to the metastatic setting, which is a completely different scenario. 

In this scenario, we know cancer cells have gotten into the bloodstream because they showed up on scans in other organs of the body. We add chemotherapy to the bloodstream to target those cancer cells in the bloodstream as well as those living in other distant organs.

Note that chemotherapy doesn't do a great job of getting into the brain. For that, we use targeted radiation therapy for a problem called brain metastasis.

This is not medical advice. Talk to your doctor before making medical decisions.