Breast Cancer Treatment
October is Breast Cancer Awareness Month, a time dedicated to spreading knowledge, supporting research, and empowering patients and healthcare providers alike. Throughout the month, we’ll explore various critical aspects of breast cancer care. In this post, we focus on the current role of targeted therapies in treatment and encourage both patients and providers to consider clinical trials when appropriate, to access cutting-edge options for care.
Breast cancer treatment has evolved significantly, especially with the use of targeted therapies. These therapies are designed to attack specific genetic mutations and pathways driving tumor growth. Unlike traditional treatments such as chemotherapy/hormonal therapy, these therapies focus on biomarkers such as HER2, PIK3CA, BRCA1/2, and others. This allows for a personalized treatment approach. Here are the key targeted therapies currently used in breast cancer:
HER2-Targeted Therapies
HER2 (Human Epidermal Growth Factor Receptor 2) is overexpressed in about 25-30% of breast cancers and is associated with aggressive tumor behavior. HER2-targeted therapies have dramatically improved outcomes for patients with HER2-positive breast cancer.
- Trastuzumab (Herceptin): This monoclonal antibody targets the HER2 receptor on cancer cells. It is used in both early-stage and metastatic breast cancer, often in combination with chemotherapy or other HER2-targeted agents.
- Pertuzumab (Perjeta): Pertuzumab is often combined with trastuzumab and chemotherapy for HER2-positive breast cancer. It blocks a different part of the HER2 receptor, improving overall response rates and progression-free survival.
- Tucatinib (HER2CLIMB): This oral tyrosine kinase inhibitor is approved for patients with HER2-positive metastatic breast cancer that has progressed after two or more prior therapies. It is often used in combination with trastuzumab and capecitabine.
- Trastuzumab Deruxtecan (T-DXd): An antibody-drug conjugate that combines trastuzumab with a chemotherapy agent, T-DXd has shown success in patients with HER2-low breast cancer (IHC 1+ or 2+), expanding treatment options for this newly defined group.
PIK3CA-Targeted Therapies
PIK3CA mutations occur in approximately 40% of patients with hormone receptor-positive, HER2-negative breast cancer.
- Alpelisib (Piqray): Approved for use in combination with fulvestrant for postmenopausal women with PIK3CA-mutated, hormone receptor-positive, HER2-negative advanced breast cancer, particularly after progression on endocrine therapy .
- Capivasertib: This AKT inhibitor has shown promise in treating patients with PIK3CA, AKT1, or PTEN mutations, offering a new line of therapy after progression on endocrine treatments .
BRCA1/2 and PARP Inhibitors
Patients with germline BRCA1 or BRCA2 mutations are at higher risk for breast cancer, and targeted therapies can be effective in these cases.
- Olaparib (Lynparza) and Talazoparib: These PARP inhibitors are used in patients with HER2-negative metastatic breast cancer who carry BRCA1/2 mutations. They work by inhibiting the enzyme PARP, leading to cancer cell death in tumors with defective DNA repair mechanisms .
Other Targeted Approaches
- FGFR Inhibitors: FGFR (Fibroblast Growth Factor Receptor) alterations, while less common, are being investigated as potential targets in breast cancer. FGFR inhibitors are being studied for use in patients with metastatic disease.
- Trop-2 Targeting: Sacituzumab govitecan is an antibody-drug conjugate that targets Trop-2, a protein expressed in many cancers and is approved for patients with metastatic triple-negative breast cancer (TNBC).
Targeted Therapy: A New Hope
Targeted therapies have revolutionized the treatment landscape for breast cancer, offering more personalized and precise options for patients with specific genetic mutations or biomarkers. As these therapies continue to evolve, they provide new hope for patients who may not have responded to traditional treatments. For patients and care providers, it is critical to explore clinical trials that offer access to these innovative therapies alone or in combination with traditional therapies or different setting such as adjuvant or neoadjuvant treatment, ensuring that all available options are considered.
About the Author
Dr. Thomas is a distinguished medical professional and a compassionate guide in the field of oncology. With over a decade of dedicated experience as a board-certified medical oncologist/internal medicine specialist, Dr. Thomas has become a trusted expert in the treatment of melanoma, sarcoma, and gastrointestinal conditions. With his many years of experience, he brings a wealth of expertise to the complex and challenging world of oncology. About Dr Thomas – MedOncMD