• Ziqi Yue, PharmD

New Advancements in Breast Cancer Treatments and Therapies

Historically, modified radical mastectomy, a surgical removal of the breast, was the primary treatment of breast cancer (Medscape 2019). However, as researchers learned about the science behind breast cancer, newer and more advanced treatments were developed. Today, there is significant research in targeted therapies for patients with breast cancer and breast conservation is much more common.

In breast cancer cells, there are three proteins that need to be tested for doctors to decide the right course of treatment: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). It is important to know if a patient tests positive or negative for these receptors to determine the appropriate treatment for breast cancer (American Cancer Society, 2019).

ER and PR are known as hormone receptors. If a patient is ER positive or PR positive, this means that the cancer cells in this patient are fed by these hormones. Endocrine therapy decreases hormone levels to slow the progression of breast cancer (Mayo Clinic, 2019). HER2 is a receptor that can promote the growth of cancer cells. In HER2 positive patients, cancer cells grow more rapidly and are at a higher risk of spreading to the brain. Fortunately, however, this type of cancer is more sensitive to targeted therapy. Researchers have focused on developing anti-HER2 medications that are able to cross the blood brain barrier. The FDA approved a new drug called Tukysa® (tucatinib) in April 2020 (National Cancer Institute, 2020). It was approved to be used in combination with Herceptin® (trastuzumab) and Xeloda® (capecitabine) in HER2 positive breast cancer that cannot be removed by surgery or in metastatic breast cancer (National Institutes of Health, 2020). A double-blind clinical trial has shown that the addition of Tukysa® improves the survival in women with cancer spreading to the brain by 24.9% in one year without the cancer further progressing (N Engl J Med, 2020).

A separate subtype is called triple-negative breast cancer, which means that the patient tests negative for all three proteins. This is harder to treat because triple-negative breast cancer does not respond to hormone therapy or anti-HER2 therapy (National Cancer Institute, 2020). A new drug Trodelvy® (sacituzumab govitecan-hziy) was approved by FDA in April 2020 to treat patients with metastatic triple-negative breast cancer, who have failed at least 2 other treatments (National Institutes of Health, 2020). Unlike traditional chemotherapy that targets rapid-growing cells, this medication delivers the chemotherapy directly to cancer cells. Based on a double-blind clinical trial for metastatic disease, it was shown to be effective in one third of patients. The median duration of reaction, which means the length of time that the patient is responsive to the treatment, is 7.7 months while on Trodelvy® (N Engl J Med, 2019).

If you are interested in learning more about treatment options for breast cancer and new therapies, please contact RangeLight Health to set up a consultation with an expert U.S.-based oncologist.

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