Advances in breast cancer research are ongoing. According to research, subtypes of breast cancer determines the treatment options. These three main breast cancer subtypes respond differently to various treatments:
- Hormone receptor (HR) positive
- Human epidermal growth factor receptor 2 (HER2) positive
- Triple-negative
1. HR positive– For this type of breast cancer, targeted therapy uses drugs or other substances to attack cancer cells with less harm to normal cells. There is a new focus on adding targeted therapies to hormone therapy for advanced or metastatic HR-positive breast cancer. These treatments could prolong the time until chemotherapy is needed and ideally, extend survival.
2. HER2 Positive– This type ofmetastatic breast cancer is more likely to spread to the brain than other types of breast cancer. HER2-targeted drugs that can cross the blood-brain barrier are being studied for the treatment and prevention of brain metastases. In 2020, the FDA approved the use of the drug tucatinib (Tukysa) combined with trastuzumab and capecitabine (Xeloda) for HER2-positive breast cancer that either can’t be removed with surgery or has spread to other parts of the body. In one study, women who received tucatinib in addition to the other two drugs lived longer both without their disease progressing and overall than women receiving only trastuzumab and capecitabine. This includes women whose cancer had spread to the brain.
3. Triple-Negative– This type of breast cancers (TNBC)are the hardest to treat because they lack both hormone receptors and HER2 overexpression, so they do not respond to therapies directed at these targets. Therefore, chemotherapy is the mainstay for treatment of TNBC. Some treatments now being used are:
- In April 2020, the FDA approved the drug sacituzumab govitecan-hziy (Trodelvy) to treat triple negative breast cancer that has spread to other parts of the body. Patients must have received at least two prior therapies before receiving the drug.
- PARP inhibitors work by blocking a protein that is used to repair damage to DNA that occurs during cell division. These drugs, which include olaparib (Lynparza) and talazoparib (Talzenna), effectively target TNBC caused by certain inherited BRCA gene mutations or other alterations that lead to defects in DNA damage repair. They are also approved for metastatic ER-positive, HER2-negative breast cancers in patients who have inherited a harmful BRCA gene mutation.
- Immunotherapy drugs have shown some promise in a small number of breast cancers, particularly those that are triple negative. Some data suggest that patients may be more likely to respond to immunotherapy if their tumor expresses the protein PD-L1 or if it has a large number of mutations.
- Scientists are also studying whether combining a variety of drugs with immunotherapy will work better than immunotherapy alone. The immunotherapy drug atezolizumab (Tecentriq) is approved to be used with chemotherapy in patients with metastatic TNBC that expresses the PD-L1 protein.
- Drugs that block the androgen receptors (AR) or prevent androgen production are being tested in a subset of TNBC cancers that express the AR.
The following are some of the latest news articles on breast cancer research and study updates:
- Having a Heart Attack May Make Breast Cancer Grow Faster
- Sacituzumab Govitecan Approved for Metastatic Triple-Negative Breast Cancer
- For Women with Breast Cancer, Regular Exercise May Improve Survival
- New Approach Uses Much Less Tissue to Analyze Tumor Proteins and Genes
- For Metastatic HER2-Positive Breast Cancer, New Treatments Emerge
- Analysis Shows Women with High Breast Cancer Recurrence Scores Benefit from Chemo
View the full list of Breast Cancer Research Results and Study Updates.
Source: National Cancer Institute https://www.cancer.gov/types/breast/research