Triple Negative Breast Cancer (TNBC)
Triple negative breast cancer (TNBC) is a subtype of breast cancer that does not express estrogen receptors, progesterone receptors, or HER2. Because these receptors are absent, hormone therapy and HER2-targeted therapy are generally not effective treatment strategies for TNBC. TNBC accounts for approximately 10–15% of breast cancers and is often considered more aggressive than hormone receptor-positive breast cancer. It may grow more quickly and has a higher risk of recurrence during the first several years after diagnosis.What Makes Triple Negative Breast Cancer Different?
Triple negative breast cancer is defined by the absence of three common treatment targets:- Estrogen receptor (ER)
- Progesterone receptor (PR)
- HER2 overexpression or amplification
Who Is More Likely to Develop TNBC?
TNBC may be more common in:- Younger women
- Women with BRCA1 mutations
- African American women
- Patients with hereditary breast cancer syndromes
Symptoms of Triple Negative Breast Cancer
Symptoms of TNBC are similar to other breast cancers and may include:- A breast lump or thickening
- Skin dimpling or changes in breast texture
- Nipple inversion
- Nipple discharge
- Breast pain
- Swollen lymph nodes under the arm or near the collarbone
Diagnosis and Staging
Diagnosis usually involves imaging and tissue biopsy. Common diagnostic tools include mammography, ultrasound, breast MRI, and biopsy. Additional imaging such as PET/CT or CT scans may be used when there is concern for lymph node involvement or metastatic disease. Pathology testing confirms whether the tumor is ER-negative, PR-negative, and HER2-negative. Additional testing may include tumor grade, Ki-67, lymphovascular invasion, PD-L1 status, and genetic testing for BRCA1, BRCA2, or other hereditary cancer mutations.Standard-of-Care Treatment for Triple Negative Breast Cancer
Treatment depends on tumor stage, lymph node involvement, genetic findings, overall health, and whether the cancer is early-stage, locally advanced, recurrent, or metastatic.Surgery
Surgery is commonly used for localized TNBC. Options may include lumpectomy, mastectomy, sentinel lymph node biopsy, or axillary lymph node dissection depending on tumor size and nodal involvement.Radiation Therapy
Radiation therapy may be recommended after lumpectomy, after certain mastectomies, or when lymph nodes are involved. Radiation is used to reduce the risk of local or regional recurrence.Chemotherapy
Chemotherapy remains one of the most important systemic treatments for TNBC. It may be given before surgery, known as neoadjuvant therapy, or after surgery, known as adjuvant therapy.Common Chemotherapy Regimens Used in TNBC
KEYNOTE-522-Based Treatment
For many patients with high-risk early-stage TNBC, treatment may include pembrolizumab combined with chemotherapy before surgery, followed by additional pembrolizumab after surgery. Chemotherapy commonly includes paclitaxel, carboplatin, doxorubicin, and cyclophosphamide.Dose-Dense AC-T
Dose-dense AC-T includes doxorubicin and cyclophosphamide followed by paclitaxel. It is commonly used in higher-risk breast cancer settings.AC-T Plus Carboplatin
Carboplatin may be added in selected TNBC cases because platinum-based chemotherapy can increase DNA damage in tumor cells, particularly in cancers with DNA repair defects.TC Chemotherapy
Docetaxel and cyclophosphamide may be considered in selected cases, often depending on stage, recurrence risk, and patient-specific factors.Common Chemotherapy Side Effects
- Fatigue
- Nausea
- Hair loss
- Low white blood cell counts
- Anemia
- Peripheral neuropathy
- Mouth sores
- Infection risk
- Menstrual or fertility changes
