Triple negative breast cancer (TNBC) is a particularly aggressive form of breast cancer that lacks three key receptors commonly targeted in other types of breast cancer treatments: estrogen, progesterone, and human epidermal growth factor receptor 2 (HER2). As a result, traditional hormone therapies and HER2-targeted treatments are ineffective against TNBC.
Understanding Triple Negative Breast Cancer
Triple negative breast cancer gets its name from the absence of three key receptors: estrogen, progesterone, and HER2. These receptors are the targets of many of the therapies used to treat other types of breast cancer. Without these receptors, TNBC is harder to treat because it doesn’t respond to hormone therapies or targeted drugs like trastuzumab (Herceptin).
TNBC is typically more aggressive than other types of breast cancer and tends to grow and spread more quickly. It is also more likely to recur within the first few years after treatment. This type of breast cancer is often diagnosed in younger women and those with a BRCA1 gene mutation, though it can affect individuals of all ages and backgrounds.
Standard Treatment Options for TNBC
Treatment for triple negative breast cancer generally involves a combination of surgery, chemotherapy, and radiation therapy. However, the specific approach can vary depending on the stage of the cancer and the overall health of the patient.
Surgery: The first step in treating many cases of TNBC is surgery to remove the tumor. If the tumor is small and localized, a lumpectomy (removal of the tumor and surrounding tissue) may be performed. If the tumor is larger, a mastectomy (removal of the entire breast) may be necessary. Lymph node dissection may also be performed to check for cancer spread.
Chemotherapy: Chemotherapy is a mainstay treatment for TNBC, particularly because it can target rapidly dividing cancer cells. This is often given before surgery (neoadjuvant chemotherapy) to shrink the tumor or after surgery (adjuvant chemotherapy) to reduce the risk of recurrence. Common chemotherapy drugs used in TNBC treatment include anthracyclines and taxanes, which can help kill cancer cells throughout the body.
Radiation Therapy: After surgery, radiation therapy may be recommended to destroy any remaining cancer cells in the breast or nearby lymph nodes. This is typically done for patients who have had a lumpectomy or those with a higher risk of recurrence.
Advances in Targeted and Immunotherapy Treatments
While traditional treatments are still widely used, significant progress has been made in developing newer therapies for TNBC, particularly immunotherapy and targeted treatments.
Immunotherapy: Immunotherapy harnesses the body’s immune system to fight cancer. For patients with TNBC, the FDA has approved the use of immunotherapy drugs like pembrolizumab (Keytruda) and atezolizumab (Tecentriq). These drugs work by blocking the PD-1/PD-L1 pathway, which helps cancer cells evade detection by the immune system. Immunotherapy has shown promise in treating metastatic TNBC or cases that have not responded to traditional therapies.
PARP Inhibitors: PARP inhibitors, such as olaparib (Lynparza), are another promising treatment for TNBC patients, particularly those with BRCA1 or BRCA2 gene mutations. These drugs target the cancer cells' DNA repair mechanisms, making it difficult for them to survive. PARP inhibitors have been shown to improve outcomes for patients with BRCA-related TNBC, both in the metastatic setting and as maintenance therapy after chemotherapy.
Antibody-Drug Conjugates (ADCs): ADCs are a new class of targeted therapies that combine antibodies with powerful chemotherapy agents. These drugs are designed to deliver chemotherapy directly to cancer cells, minimizing damage to surrounding healthy tissue. For example, sacituzumab govitecan (Trodelvy) is an ADC that has been approved for metastatic TNBC and has shown efficacy in patients who have previously undergone multiple treatments.
The Role of Clinical Trials in Triple Negative Breast Cancer
Because TNBC is an aggressive form of cancer, researchers continue to explore new therapies and treatment combinations to improve patient outcomes. Clinical trials are a critical avenue for developing and testing innovative treatments for TNBC. Patients with triple negative breast cancer may be eligible to participate in clinical trials that are testing new drugs, combination therapies, or treatment approaches.
Participating in a clinical trial can provide patients access to the latest advancements in cancer treatment, though it’s important to weigh the potential risks and benefits. Before enrolling in a clinical trial, patients should consult with their oncologist to determine whether a particular trial is appropriate for their condition.