Medical Oncology · Triple-Negative Breast Cancer

Treating Triple-Negative Breast Cancer (TNBC)

At a Glance

Treatment for triple-negative breast cancer depends on stage, tumor markers, and inherited mutations. Selected high-risk early disease often receives pembrolizumab with chemotherapy before surgery, while residual or metastatic disease may require medicines such as capecitabine, olaparib, or sacituzumab.

Triple-Negative Breast Cancer (TNBC) is a subtype that lacks the three most common “targets” found in breast cancer: estrogen receptors, progesterone receptors, and the HER2 protein ^[1]. Because these targets are missing, hormone therapy and HER2-targeted drugs are not effective. Instead, treatment relies on integrating local therapies (like breast surgery and radiation) with a combination of chemotherapy, immunotherapy, and newer “smart” drugs called antibody-drug conjugates (ADCs) ^[2]^[3].

Early-Stage TNBC: The “Neoadjuvant” Approach

For selected stage II-III or high-risk early TNBC (generally tumors that are 2 centimeters or larger, or if the cancer has spread to the lymph nodes), the standard of care is neoadjuvant therapy—systemic treatment given before surgery ^[4].

The most common regimen (based on the KEYNOTE-522 trial) combines pembrolizumab (an immunotherapy drug) with a “cocktail” of chemotherapies ^[5]:

Phase 1: You receive pembrolizumab plus paclitaxel and carboplatin ^[5].
Phase 2: You receive pembrolizumab plus an anthracycline (like doxorubicin) and cyclophosphamide ^[5].

After surgery and radiation, the goal is to continue pembrolizumab for up to nine more cycles to further reduce the risk of the cancer returning, though this trial-based plan can be modified by toxicity or treatment delays ^[6]. This total course of 17 cycles has been shown to significantly improve survival regardless of your PD-L1 status (PD-L1 testing is not required for this early-stage pembrolizumab indication) ^[6].

Post-Surgery Options: Addressing “Residual Disease”

After surgery, a pathologist examines the tissue. If no active cancer cells are found, it is called a pathologic complete response (pCR), which is a very positive sign ^[7]. However, if some cancer cells remain (residual disease), it does not mean treatment has failed, but your doctor may recommend additional, individualized “clean-up” treatments:

Capecitabine (Xeloda): This is an oral chemotherapy pill. Research from the CREATE-X trial shows that taking capecitabine for about six months can significantly improve survival for TNBC patients with residual disease ^[8]. Because the major trials for this predated routine pembrolizumab use, the sequencing of capecitabine with ongoing immunotherapy is an individualized decision.
Olaparib (Lynparza): If you have an inherited germline BRCA1 or BRCA2 mutation and specific high-risk early-stage eligibility criteria from the OlympiA trial, your doctor may prescribe this PARP inhibitor for one year ^[9]. In the OlympiA trial, olaparib reduced the risk of recurrence and improved overall survival in this specific group ^[10].

Treating Metastatic TNBC

If TNBC has spread to other parts of the body, the treatment plan depends heavily on the “markers” found in the tumor or your blood ^[11].

Immunotherapy (PD-L1+)

Your doctor will test your tumor for a protein called PD-L1. If your metastatic Combined Positive Score (CPS) is 10 or higher, the combination of pembrolizumab plus chemotherapy is often the preferred first-line treatment ^[12]. This combination has been shown to help patients live longer compared to chemotherapy alone ^[13].

Antibody-Drug Conjugates (ADCs)

Sacituzumab govitecan (Trodelvy) is a specialized drug used for metastatic TNBC, usually after you have already received at least two prior chemotherapy treatments ^[14]. It acts like a “homing missile,” delivering a potent chemotherapy payload directly to the cancer cells ^[15]. In the ASCENT trial, this drug significantly improved both progression-free and overall survival for patients with advanced TNBC ^[14].

Monitoring and Side Effects

Because TNBC treatments can be intensive, close monitoring is essential:

Immunotherapy: Pembrolizumab can cause the immune system to attack healthy organs. Your team will watch for signs of “immune-related adverse events,” such as lung inflammation (pneumonitis), skin rashes, or thyroid issues ^[16].
Chemotherapy and ADCs: Common side effects include low white blood cell counts (neutropenia), fatigue, and diarrhea ^[17]. For capecitabine, a specific side effect called hand-foot syndrome (redness, swelling, or peeling on the palms and soles) is common and may require dose adjustments ^[8]^[18].

While TNBC is considered aggressive, these newer, targeted approaches are helping more patients achieve better outcomes than ever before ^[6].

Common questions in this guide

What is the usual treatment for high-risk or early-stage TNBC?

Selected people with stage II or III, or otherwise high-risk, early-stage TNBC may receive pembrolizumab with chemotherapy before surgery. Treatment commonly includes surgery and radiation, followed by continued pembrolizumab for part of the overall course, although the plan may change because of side effects or delays.

What happens if cancer remains after surgery for TNBC?

Cancer remaining in the surgical tissue is called residual disease and does not automatically mean treatment has failed. Depending on your risk and previous treatment, your doctor may discuss capecitabine or, for people meeting specific criteria with an inherited BRCA1 or BRCA2 mutation, olaparib. How these medicines are timed with pembrolizumab is individualized.

How does PD-L1 testing affect metastatic TNBC treatment?

For metastatic TNBC, a PD-L1 test reports a Combined Positive Score, or CPS. When the CPS is 10 or higher, pembrolizumab combined with chemotherapy is often a preferred first treatment. PD-L1 testing is not required for the pembrolizumab indication described for selected early-stage TNBC.

What medicines can treat metastatic triple-negative breast cancer?

Treatment for metastatic TNBC depends on tumor markers, previous treatments, and your overall health. Pembrolizumab with chemotherapy may be used when PD-L1 CPS is 10 or higher, and sacituzumab govitecan may be considered after at least two prior chemotherapy treatments.

What side effects should I watch for during TNBC treatment?

Pembrolizumab can cause the immune system to affect healthy organs, leading to problems such as lung inflammation, skin rash, or thyroid changes. Chemotherapy and antibody-drug conjugates can cause low white blood cell counts, fatigue, or diarrhea, while capecitabine commonly causes redness, swelling, or peeling of the hands and feet. Report new or worsening symptoms promptly to your treatment team.

Who may be eligible for olaparib after treatment for early TNBC?

Olaparib may be offered for one year to some people with an inherited germline BRCA1 or BRCA2 mutation who also meet specific high-risk early-stage eligibility criteria. It is not appropriate for every person with TNBC, so your oncology team will review your genetic result, stage, and prior treatment.

Curated prompts to bring to your next appointment.

1.Based on the size and location of my tumor, is the 'KEYNOTE-522' regimen (pembrolizumab plus chemotherapy) the right starting point for me?
2.If I don't achieve a 'pathologic complete response' (pCR) after surgery, what are the next steps for my treatment (e.g., capecitabine or olaparib)?
3.Should I have my tumor tested for PD-L1 levels right away, especially if we are discussing metastatic treatment?
4.If I have an inherited BRCA mutation, when is the best time to start a PARP inhibitor like olaparib?
5.What is our plan for monitoring and managing potential immune-related side effects from pembrolizumab?

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

Key takeaways

Selected patients with stage II or III or high-risk early TNBC may receive pembrolizumab with chemotherapy before surgery, followed by surgery, radiation, and continued pembrolizumab.
A pathologic complete response is encouraging, while residual cancer may lead to individualized treatment with capecitabine or, for eligible people with inherited BRCA1 or BRCA2 mutations, olaparib.
For metastatic TNBC, PD-L1 testing helps guide pembrolizumab plus chemotherapy, especially when the combined positive score is 10 or higher.
Sacituzumab govitecan is an option for some metastatic TNBC patients after at least two prior chemotherapy treatments.
Pembrolizumab, chemotherapy, and antibody-drug conjugates require monitoring for immune-related problems, neutropenia, fatigue, diarrhea, and other side effects.

References (18)

1
Triple negative breast cancer: Pitfalls and progress.
Zagami P, Carey LA
NPJ breast cancer 2022; (8(1)):95 doi:10.1038/s41523-022-00468-0.
PMID: 35987766
2
Medical Therapy for Hormone Receptor-Positive, HER2-Negative Stage I-III Breast Cancer: ASCO Living Guideline, Version 2026.1.0.
Caswell-Jin JL, Somerfield MR, Khan MA, et al.
Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2026; 101200JCO2602034 doi:10.1200/JCO-26-02034.
PMID: 42647767
3
Neoadjuvant Chemotherapy, Endocrine Therapy, and Targeted Therapy for Breast Cancer: ASCO Guideline.
Korde LA, Somerfield MR, Carey LA, et al.
Journal of clinical oncology : official journal of the American Society of Clinical Oncology 2021; (39(13)):1485-1505 doi:10.1200/JCO.20.03399.
PMID: 33507815
4
Progress in immune checkpoint inhibition in early-stage triple-negative breast cancer.
Mohamed A, Kruse M, Tran J
Expert review of anticancer therapy 2023; (23(10)):1071-1084 doi:10.1080/14737140.2023.2262764.
PMID: 37747062
5
Surgical Outcomes After Neoadjuvant Pembrolizumab Plus Chemotherapy for Triple-Negative Breast Cancer: Results from the Randomized, Placebo-Controlled Phase 3 KEYNOTE-522 Study.
Kuemmel S, Fasching PA, Schmid P, et al.
Annals of surgical oncology 2026; (33(6)):5550-5557 doi:10.1245/s10434-026-19121-2.
PMID: 41739398
6
Overall Survival with Pembrolizumab in Early-Stage Triple-Negative Breast Cancer.
Schmid P, Cortes J, Dent R, et al.
The New England journal of medicine 2024; (391(21)):1981-1991 doi:10.1056/NEJMoa2409932.
PMID: 39282906
7
Management of patients with early-stage triple-negative breast cancer following pembrolizumab-based neoadjuvant therapy: What are the evidences?
Bonadio RC, Tarantino P, Testa L, et al.
Cancer treatment reviews 2022; (110()):102459 doi:10.1016/j.ctrv.2022.102459.
PMID: 35998514
8
Adjuvant Capecitabine for Breast Cancer after Preoperative Chemotherapy.
Masuda N, Lee SJ, Ohtani S, et al.
The New England journal of medicine 2017; (376(22)):2147-2159 doi:10.1056/NEJMoa1612645.
PMID: 28564564
9
Adjuvant Olaparib for Patients with BRCA1- or BRCA2-Mutated Breast Cancer.
Tutt ANJ, Garber JE, Kaufman B, et al.
The New England journal of medicine 2021; (384(25)):2394-2405 doi:10.1056/NEJMoa2105215.
PMID: 34081848
10
Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high-risk, early breast cancer.
Geyer CE, Garber JE, Gelber RD, et al.
Annals of oncology : official journal of the European Society for Medical Oncology 2022; (33(12)):1250-1268 doi:10.1016/j.annonc.2022.09.159.
PMID: 36228963
11
New Perspectives in the Management of Triple-Negative Breast Cancer.
Bartsch R, Bago-Horvath Z, Egle D, et al.
Breast care (Basel, Switzerland) 2026; (21(2)):152-165 doi:10.1159/000547988.
PMID: 41063764
12
Pembrolizumab plus Chemotherapy in Advanced Triple-Negative Breast Cancer.
Cortes J, Rugo HS, Cescon DW, et al.
The New England journal of medicine 2022; (387(3)):217-226 doi:10.1056/NEJMoa2202809.
PMID: 35857659
13
Pembrolizumab plus chemotherapy versus placebo plus chemotherapy for previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer (KEYNOTE-355): a randomised, placebo-controlled, double-blind, phase 3 clinical trial.
Cortes J, Cescon DW, Rugo HS, et al.
Lancet (London, England) 2020; (396(10265)):1817-1828 doi:10.1016/S0140-6736(20)32531-9.
PMID: 33278935
14
Sacituzumab Govitecan in Metastatic Triple-Negative Breast Cancer.
Bardia A, Hurvitz SA, Tolaney SM, et al.
The New England journal of medicine 2021; (384(16)):1529-1541 doi:10.1056/NEJMoa2028485.
PMID: 33882206
15
Trastuzumab Deruxtecan after Endocrine Therapy in Metastatic Breast Cancer.
Bardia A, Hu X, Dent R, et al.
The New England journal of medicine 2024; (391(22)):2110-2122 doi:10.1056/NEJMoa2407086.
PMID: 39282896
16
Immune-related adverse events among patients with early-stage triple-negative breast cancer treated with pembrolizumab plus chemotherapy: real-world data from the Neo-Real/GBECAM 0123 study.
Andrade MO, Gutierres IG, Tavares MC, et al.
Breast (Edinburgh, Scotland) 2025; (83()):104473 doi:10.1016/j.breast.2025.104473.
PMID: 40240201
17
Safety analyses from the phase 3 ASCENT trial of sacituzumab govitecan in metastatic triple-negative breast cancer.
Rugo HS, Tolaney SM, Loirat D, et al.
NPJ breast cancer 2022; (8(1)):98 doi:10.1038/s41523-022-00467-1.
PMID: 36038616
18
The adjuvant use of capecitabine for residual disease following pre-operative chemotherapy for breast cancer: Challenges applying CREATE-X to a US population.
Beyerlin K, Jimenez R, Zangardi M, et al.
Journal of oncology pharmacy practice : official publication of the International Society of Oncology Pharmacy Practitioners 2021; (27(8)):1883-1890 doi:10.1177/1078155220971751.
PMID: 33153384

This page is for informational purposes only and does not constitute medical advice. Treatment choices for TNBC depend on your stage, biomarkers, genetic results, and overall health, so discuss options and side-effect concerns with your oncology team.

Get notified when new evidence is published on Her2-receptor negative breast cancer.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.

Guide Contents