Triple Negative Breast Cancer Treatment Protocol
For patients with triple negative breast cancer (TNBC), the recommended treatment protocol includes neoadjuvant chemotherapy with immunotherapy for stage II/III disease, followed by surgery and appropriate adjuvant therapy based on response. 1
Early Stage TNBC (Stage I-III)
Neoadjuvant Therapy
- Neoadjuvant therapy is strongly recommended as standard approach for stage II and III TNBC, allowing for tumor downstaging, assessment of pathologic complete response (pCR), and opportunity to tailor adjuvant therapy 1
- Preferred regimen for stage II/III TNBC: chemotherapy with taxanes, carboplatin, anthracyclines, and cyclophosphamide, combined with concurrent pembrolizumab 1
- Benefit from pembrolizumab is independent of PD-L1 status 1
- Sequential anthracycline-based regimens followed by taxanes are an evidence-based alternative option 1, 2
- For stage I TNBC, consider adding carboplatin and pembrolizumab for higher-risk disease 1
Post-Neoadjuvant Therapy
- For patients with residual disease after standard neoadjuvant chemotherapy, adjuvant capecitabine for 6-8 cycles is recommended if germline BRCA1/2 wild-type 1, 2
- Regardless of response to neoadjuvant chemotherapy plus pembrolizumab, ongoing adjuvant pembrolizumab is recommended 1
- For patients with germline BRCA1/2 mutations, PARP inhibitors may be considered in the adjuvant setting 2
Surgery
- TNBC is characterized by an expanding growth pattern without extensive intraductal spread, making it suitable for breast-conserving therapy (BCT) with sufficient margins 3
- Sentinel node biopsy and axillary evaluation should be performed with caution due to higher regional recurrence rates in TNBC compared to other subtypes 3
Radiation Therapy
- Postoperative radiation therapy is strongly recommended after breast-conserving surgery 2
- Consider post-mastectomy radiation therapy for patients with T3-T4 tumors and/or ≥4 positive axillary nodes 2
- Radiation therapy of the chest wall after mastectomy and regional area should be considered due to its demonstrated usefulness in TNBC 3
Metastatic TNBC
First-Line Therapy
- For PD-L1-positive metastatic TNBC: immune checkpoint inhibitor plus chemotherapy (atezolizumab plus nab-paclitaxel or pembrolizumab plus chemotherapy) 2
- For PD-L1-negative metastatic TNBC: single-agent chemotherapy is preferred over combination chemotherapy, though combination regimens may be considered for symptomatic or immediately life-threatening disease 2
- Platinum-based or non-platinum-based regimens can be offered based on individual assessment 2
Subsequent Lines of Therapy
- For patients who have received at least two prior therapies for metastatic disease: sacituzumab govitecan is strongly recommended 2
- For patients with germline BRCA1/2 mutations previously treated with chemotherapy: PARP inhibitors (olaparib or talazoparib) are preferred over chemotherapy 2
Special Considerations
Germline BRCA1/2 Mutations
- Patients with TNBC should undergo genetic testing for germline BRCA1/2 mutations 2
- PARP inhibitors demonstrate high response rates in TNBC with DNA repair defects, including germline BRCA1/2 and PALB2 mutations 2
- Note that randomized PARP inhibitor trials did not directly compare with taxanes, anthracyclines, or platinums 2
Treatment Response Monitoring
- Patients should be closely observed during neoadjuvant chemotherapy 3
- If there is evidence of tumor progression during neoadjuvant therapy, consider modifying the chemotherapeutic regimen or proceeding to surgery 3
- After achieving pCR, outcomes are generally good; however, patients with residual disease after neoadjuvant therapy have higher risk of recurrence and should receive appropriate adjuvant therapy 3, 1
Follow-up and Survivorship
- Regular follow-up with ipsilateral and contralateral mammography every 1-2 years 2
- Close monitoring during the first 3 years after treatment completion due to higher risk of early recurrence in TNBC 3, 4
- No evidence that additional laboratory or imaging tests improve survival in asymptomatic patients 2