The first 60 days: Triple-negative breast cancer (TNBC)
A breast cancer that lacks the three receptors (oestrogen, progesterone, HER2) that other breast cancers can be treated through. It was the hardest subtype for decades; since 2020 immunotherapy and ADCs have changed that. Below, week by week, is what OnCo's record of Triple-negative breast cancer (TNBC) says about the first two months: the order is typical, the timing is yours to ask about. Sections appear only where the record has something to say. Orientation, not medical advice.
Weeks 1 to 2
What happens now
Staging tests establish exactly what and where the cancer is. Everything else follows from the answers.
From the recorded treatment journey
- Core biopsy with receptor testing (ER, PR, HER2), breast imaging, and staging scans for stage II-III; germline BRCA testing.
Biomarkers your report may list
PD-L1 (22C3 CPS ≥10 for metastatic pembrolizumab)Germline BRCA1/2 and PALB2 (PARP inhibitors, surgery choices)HRD scoreTILs (prognostic; de-escalation trials)HER2-low status (T-DXd eligibility)TROP2 (not required for TROP2 ADCs; PET tracers in development)Ki-67, gradectDNA/MRD (Signatera, investigational)AR (LAR subtype trials)TMB / MSI (rare, tumour-agnostic IO)
Ask which of these were tested and what the results were; see the report reader for what each value means.
Tests and imaging linked to this cancer
How it is staged
These specialties appear in the standard of care for this cancer. In most centres they meet weekly as a tumour board to agree each plan; you can ask when yours was discussed and what was decided.
- PathologistNamed in the standard of care for: Stage I (T1a-b N0).
- SurgeonNamed in the standard of care for: Stage I (T1a-b N0), Stage II-III.
- Medical oncologistNamed in the standard of care for: Stage I (T1a-b N0), Stage II-III, Metastatic, first line, PD-L1 CPS ≥10, Metastatic, first line, PD-L1 negative or PD-1 ineligible and 1 more.
- Clinical oncologist (radiotherapy)Named in the standard of care for: Stage I (T1a-b N0), Stage II-III.
A second opinion from a centre that treats many similar cases is normal, not rude; the standard of care tells you what to compare it against.
Each row is a setting from the standard of care, in the order it usually arises. Not all will apply to you; your stage and biomarkers decide which do. The guideline grade, where recorded, says how strong the evidence is.
Surgery ± radiation; chemotherapy for ≥T1c; TIL-high tumours have >90% 5-year RFS even without chemotherapy (OPTimal, ETNA, TIL-CHOICE cohorts). De-escalation trials ongoing.
- 2.Stage II-IIINCCN category Category 1, preferred: neoadjuvant pembrolizumab + chemotherapy (KEYNOTE-522); adjuvant olaparib for gBRCA Category 2A, preferred, ESMO-MCBS A (KEYNOTE-522); A (OlympiA), NCCN Guidelines: Breast Cancer
Neoadjuvant pembrolizumab + carboplatin/paclitaxel → AC/EC, surgery, adjuvant pembrolizumab (KEYNOTE-522). Germline BRCA + residual disease: olaparib 1 year (OlympiA). Residual disease without BRCA: capecitabine (CREATE-X). Radiation per stage.
- 3.Metastatic, first line, PD-L1 CPS ≥10NCCN category Category 1, preferred: sacituzumab govitecan + pembrolizumab (NCCN Breast, February 2026); pembrolizumab + chemotherapy Category 1, ESMO-MCBS 4 (KEYNOTE-355), NCCN Guidelines: Breast Cancer
Pembrolizumab + chemotherapy (KEYNOTE-355) or sacituzumab govitecan + pembrolizumab (ASCENT-04, approved 2026).
- 4.Metastatic, first line, PD-L1 negative or PD-1 ineligibleNCCN category Category 1, preferred: sacituzumab govitecan monotherapy (NCCN Breast, 2026), NCCN Guidelines: Breast Cancer
Datopotamab deruxtecan (TROPION-Breast02, OS benefit) or sacituzumab govitecan (ASCENT-03), both approved 2026; PARP inhibitor if germline BRCA; chemotherapy.
- 5.Metastatic, later linesESMO-MCBS 4 (ASCENT; re-scored 5 in the breast-cancer analysis); 4 (DESTINY-Breast04), NCCN Guidelines: Breast Cancer
Whichever TROP2 ADC was not used first (cross-resistance uncertain); T-DXd if HER2-low (DESTINY-Breast04); iza-bren where available; chemotherapy (eribulin, capecitabine); clinical trials.
Decision points in the recorded journey, Stage II-III (operable)
- Did the pathology show a complete response (pCR)?
Written by hand for this cancer. Take the group that matches where you are. To tick, add your own and print, open the one-page appointment sheet.
Newly diagnosed
- What exactly makes my cancer 'triple-negative', and was HER2 scored as 0, 1+, or 2+?HER2-low (1+ or 2+ without amplification) tumours qualify for trastuzumab deruxtecan later; the difference between 0 and 1+ matters.
- Have I been referred for germline genetic testing (BRCA1/2, PALB2 and others)?Guidelines recommend it for all TNBC. A BRCA result changes surgery options, opens PARP inhibitors, and matters for relatives.
- What is my clinical stage, and which imaging was used to determine it?Stage decides whether treatment starts with surgery or with chemo-immunotherapy; PET/CT is often used for stage II-III.
- What was my tumour-infiltrating lymphocyte (TIL) score, and does it change my options?Very small, TIL-rich tumours have excellent outcomes; TIL status is being used to de-escalate treatment in trials.
- Is fertility preservation relevant for me, and do we have time before treatment starts?Chemotherapy can affect fertility; egg or embryo freezing needs to happen before the first cycle.
Before surgery (neoadjuvant)
- Will I receive pembrolizumab with chemotherapy before surgery, as in KEYNOTE-522, and if not, why not?This regimen improved survival for stage II-III TNBC and is the standard of care for most patients.
- Which side effects of immunotherapy should I watch for, and who do I call at any hour?Immune-related side effects (thyroid, colitis, adrenal) are treatable if caught early; some are permanent.
- Is there a clinical trial testing less chemotherapy (for example without anthracyclines) or a newer drug that I might join?SCARLET and other trials test whether some of the toughest chemotherapy can be dropped without losing effect.
- Am I a candidate for scalp cooling, and does the centre offer it?It preserves hair in about half of patients on taxane-based regimens.
After surgery
- Did I have a pathologic complete response (pCR), and if not, what was my residual cancer burden (RCB)?pCR predicts a very good outlook; residual disease means extra treatment such as capecitabine or olaparib is discussed.
- If I carry a BRCA mutation and had residual disease, will I be offered a year of olaparib?OlympiA showed adjuvant olaparib improves survival in this group.
- Will I continue pembrolizumab after surgery, and is there a trial testing whether I can stop early if I had a pCR?OptimICE-pCR is testing whether the adjuvant year of immunotherapy is needed after a complete response.
- Is there a role for blood tests for circulating tumour DNA (MRD) in my follow-up, in a trial or otherwise?ctDNA detects relapse months before scans; interventional trials are testing acting on it.
- What surveillance schedule will I have, and which symptoms should prompt an early call?TNBC relapses cluster in the first three years; knowing what to report reduces delay.
- Can I get a structured exercise programme and a survivorship plan, including heart health checks?Exercise improved survival in colon cancer trials and reduces fatigue; anthracyclines can affect the heart.
Metastatic
- What is my PD-L1 combined positive score (CPS) on the most recent biopsy?CPS 10 or more opens pembrolizumab combinations, including with the ADC sacituzumab govitecan.
- Which first-line option do you recommend for me: sacituzumab govitecan, datopotamab deruxtecan, or immunotherapy plus chemotherapy, and why?Two TROP2 ADCs were approved first-line in 2026 with different side-effect profiles (neutropenia and diarrhoea vs stomatitis and eye effects).
- Is my tumour HER2-low, making trastuzumab deruxtecan an option later?About a third of TNBC is HER2-low; T-DXd is approved in that setting after chemotherapy.
- If one ADC stops working, what is the plan for the next one, given that they may share resistance?Back-to-back ADCs with the same payload class often work less well; sequencing is an open question worth discussing.
- Was a new biopsy or liquid biopsy taken at progression to re-check receptors and look for a trial-matching mutation?Receptor status can change; comprehensive genomic profiling can reveal rare targetable alterations.
- Which clinical trials, including bispecific ADCs and newer TROP2 ADCs, could I be eligible for here or at a referral centre?Izalontamab brengitecan and sacituzumab tirumotecan are in phase 3 trials that may be recruiting.
- Have you screened for brain metastases, and how will we monitor for them?Brain involvement is common in metastatic TNBC and is treated differently.
- What supportive-care and palliative-care resources can be involved now, not later?Early palliative care improves quality of life and sometimes survival, alongside active treatment.
Trials open now for this cancer in OnCo, largest phase first. Joining a trial is a decision like any other: ask what the comparison arm is, whether a placebo is used, and what happens if you leave. The cancer page searches ClinicalTrials.gov live for more.
- A Clinical Study of Sacituzumab Tirumotecan (Sac-TMT, MK-2870) in People With Breast Cancer (MK-2870-032)Phase 3 · recruiting · NCT06966700A Phase 3, Randomized, Open-label Study to Evaluate the Efficacy and Safety of Sac-TMT (Sacituzumab Tirumotecan, MK-2870) Followed by Carboplatin/Paclitaxel vs Chemotherapy, Both in Combination With Pembrolizumab as Neoadjuvant Therapy for High-Risk, Early-Stage, Triple-Negative Breast Cancer or Hormone Receptor-low Positive/Human Epidermal Growth Factor Receptor-2 Negative Breast Cancer
- A Clinical Trial of SHR-A1811 in the Treatment of Triple-negative Breast CancerPhase 3 · recruiting · NCT07111832A Phase III, Multicenter, Randomized, Open-label, Active-controlled Study of SHR-A1811 Plus SHR-1316 Versus Toripalimab Plus Nab-paclitaxel in PD-L1-positive Locally Recurrent Unresectable or Metastatic Triple-negative Breast Cancer
- A Phase III Study of ESG401 for Unresectable Recurrent or Metastatic Triple-Negative Breast CancerPhase 3 · recruiting · NCT06732323A Randomized, Open-label, Phase III Study of ESG401 Versus Investigator's Choice Chemotherapy as First-line Treatment in Patients With Unresectable Recurrent or Metastatic Triple-Negative Breast Cancer
- A Phase III Study of JSKN016 Versus Treatment of Physician's Choice in Patients With Triple-Negative Breast Cancer Who Have Failed Standard of CarePhase 3 · recruiting · NCT07533123A Randomized, Controlled, Open-Label Study of JSKN016 Versus Treatment of Physician's Choice in Patients With Unresectable Locally Advanced, Recurrent, or Metastatic Triple-Negative Breast Cancer Who Have Failed at Least Two Lines of Prior Systemic Therapy
- A Study of Sacituzumab Tirumotecan (Sac-TMT, MK-2870) as Monotherapy and in Combination With Pembrolizumab (MK-3475) in Participants With Triple-Negative Breast Cancer (MK-2870-011/TroFuse-011)Phase 3 · recruiting · NCT06841354A Phase 3, Randomized, Open-label Study Comparing Efficacy and Safety of Sacituzumab Tirumotecan (Sac-TMT, MK-2870) as a Monotherapy and in Combination With Pembrolizumab (MK-3475) Versus Treatment of Physician's Choice in Participants With Previously Untreated Locally Recurrent Unresectable or Metastatic Triple-Negative Breast Cancer Expressing PD-L1 at CPS Less Than 10 (TroFuse-011)
Much of what helps in the first weeks is free if you know to ask: testing, helplines, rides and lodging, second opinions, trial travel.
- Triple-negative breast cancer (TNBC): the full pageA breast cancer that lacks the three receptors (oestrogen, progesterone, HER2) that other breast cancers can be treated through. It was the hardest subtype for decades; since 2020 immunotherapy and ADCs have changed that.
- One-page appointment sheetYour questions, the words you may hear, what to bring, and space for the answers. Print it.
- Treatment journey: Stage II-III (operable)About a year of active treatment: chemotherapy with immunotherapy before surgery, surgery, then immunotherapy for nine more cycles, with radiotherapy alongside, followed by five years of check-ups.
- Guidelines comparedNCCN, ESMO and NICE side by side for this cancer.
- Treatment sequencingWhich treatment tends to follow which, line by line.
- NavigatorStandard of care for your stage, what you have tried, and trials near you.
Words this page and the cancer page use
- Tumour-infiltrating lymphocytes (TILs): Immune cells that have got inside the tumour.
- Residual cancer burden (RCB): A pathology score for how much cancer remains in the breast and lymph nodes after pre-surgery treatment, from 0 (none) to III (a large amount), combining tumour bed size, cellularity and nodal involvement.
- Homologous recombination deficiency (HRD): A tumour that cannot properly repair double-strand DNA breaks, usually because of BRCA or related gene loss.
- HER2-low and HER2-ultralow: Tumours with a little HER2 (IHC 1+ or 2+ without amplification), or a trace (ultralow), which older HER2 drugs ignored but Enhertu can attack.
- PAM50 / intrinsic subtypes: A 50-gene test that sorts breast cancers into luminal A, luminal B, HER2-enriched, and basal-like.
- ADC sequencing: The open question of whether a second ADC works after the first one fails, especially when both carry the same type of payload.
- Cancer health disparities and equity: Systematic differences in who gets cancer, how early it is found and who survives, driven by race, income, geography, insurance and structural racism rather than biology alone.
- Hormone receptor status (ER / PR): Whether a breast cancer's cells carry receptors for oestrogen (ER) and progesterone (PR).
- Dose-dense and metronomic chemotherapy: Two opposite ways of rescheduling the same drugs: dose-dense gives standard doses more often (every two weeks instead of three, supported by growth factors) to deny the tumour recovery time; metronomic gives small doses continuously to attack tumour blood vessels with little toxicity.
- Lumpectomy (breast-conserving surgery): Removing only the tumour with a rim of normal breast, keeping the breast; almost always followed by radiotherapy.
Every term links to the glossary.