Dr. Jeanna Walsh, M.D., from New Hampshire Oncology and Hematology spoke recently at Concord Hospital about metastatic breast cancer types, treatments, and exciting advances in care.

“We know a lot more about the biology of metastatic breast cancer now and we can take advantage of that to extend and ensure quality of life,” said Dr. Walsh.

What are the different subtypes of metastatic breast cancer?

Metastatic breast cancer (MBC) is cancer of the breast that has spread to lymph nodes and/or other parts of the body. Overall, the five-year survival rate is 29 percent. In general, MBC is categorized into three different subtypes: estrogen receptor (ER) positive, human epidermal growth factor receptor 2 (HER2) positive, and triple negative (TN). Triple negative is arguably the most aggressive, the most likely to metastasize, but also the one for which we have the fewest tools to combat.

However, survival is on a spectrum and statistics cannot tell you what an individual patient will do; you have to start treatment first to know. Though the types have differing main treatment options, radiation and bone strengthening medications play a role in all.

How is ER positive MBC treated?

The philosophy of the treatment of MBC in general is to use the least toxic therapy that will be the most effective. Treating ER positive MBC in this manner involves trying to manipulate the estrogen piece; in other words, trying to take away the hormone that is stimulating the growth of cancer cells. To do this, surgery to remove the ovaries, medications, or both are used to stop the production of estrogen.

However, even post-menopausal women produce estrogen from their adrenal glands and fat cells, and so another medication to block estrogen from getting to a cancer cell is also necessary. On average, patients with ER positive MBC will cycle through six different hormonal programs before ultimately switching to chemotherapy.

How is HER2 positive MC treated?

HER2 positive MBCs are also either ER positive or ER negative. HER2 positive/ER positive MBCs receive the aforementioned hormonal treatments plus HER2 targeted therapy. HER2 targeted therapy involves attaching to and blocking the receptors that signal the cancer cells’ growth, slowing or even stopping it. HER2 positive/ER negative MBCs get chemotherapy in addition to HER2 targeted therapy. An exciting advancement here is the use of antibody drug conjugates; therapy that utilizes HER2 targeting to deliver a potent chemotherapy agent directly to the cancer cells. This drastically decreases the amount of chemotherapy freely roaming in the bloodstream, which can hurt healthy tissue.

How is TNMBC treated?

As previously mentioned, this particular type has the fewest treatment options available. Until recently, chemotherapy was really the only choice. With a notoriously poor prognosis, TNMBCs now have new treatments available affording renewed hope to these patients. An antibody drug conjugate that targets an overexpressed molecule called Trop-2 allows for chemotherapy to be delivered directly to the cancer cells to kill them.

Also, a game-changing advancement, targeted immunotherapy, uses next generation sequencing to look at the cancer itself and its specific mutations to fight it more effectively. Immunotherapy is arguably the most exciting thing to happen to solid tumor oncology recently.

How are new treatments developed?

Clinical trials are the path to new and improved cancer treatments and lead to FDA authorization. These trials are critically important in oncology because the physicians can only use FDA-approved treatments and it can take many years to advance through the process. Phase1 and Phase2 trials are the fact-finding steps, whereas Phase3 can lead to approval of drugs by testing them rigorously in a randomized and controlled fashion. Many patients participate in trials to potentially receive the next breakthrough treatment. Patients are many times driven, as the researchers and healthcare providers are, to further the science and increase life expectancy and quality of life for future patients.

Dr. Jeanna Walsh, M.D., of NH Oncology and Hematology spoke about metastatic breast cancer treatment at the October Concord Hospital Trust “What’s Up Doc?” Donor Lecture Series. She was introduced by Cassie Delude, APRN, from the Concord Hospital Breast Cancer Center. The monthly series, supported by the Walker Lecture Fund, features members of Concord Hospital’s medical staff speaking to Concord Hospital Trust donors about new and innovative medical treatments and services. You can watch Dr. Walsh’s presentation on Concord Hospital’s YouTube channel at: youtube.com/concordhospital.

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