Selection by stage, and the price of treating everyone
No biological variable in routine use changes the regimen, so stage decides it and the permanent toxicities fall on patients who would have been cured anyway.
1 · Risk assessment and treatment selection
Early disease · TNBC · post-neoadjuvant
Allocating further treatment on what surgery finds
What is the cytotoxic backbone that everything else in this subtype is added to?
Rationale
In the other two subtypes chemotherapy is the thing being spared. Here it is the backbone, and every addition tested in this part is an addition to it. What that backbone should be was settled in trials enrolled without regard to receptor status, which is the reason it is rarely stated explicitly in a chapter about this subtype.
Experiment
Randomised additions, substitutions and schedule changes on an anthracycline and taxane combination, mostly in unselected populations. Separately, within this subtype, a platinum and taxane regimen randomised against an anthracycline-containing one, and a nab-paclitaxel substitution tested preoperatively in HER2-negative disease.
Finding
The taxane addition and the shortened interval hold. Within this subtype specifically, replacing the anthracycline with a platinum improved disease-free survival in one trial. Substituting nab-paclitaxel for paclitaxel did not raise the pathological complete response rate, and substituting capecitabine for standard chemotherapy in older patients was worse.
Limitation
The generalisable part of this record was not randomised within this subtype, and the part that was comes from a single trial in one population. That trial compared its regimen against a control arm predating checkpoint blockade. The question it answers is not the question a clinic now asks.
Next question
If the backbone changes because immunotherapy is now added to it, does the platinum comparison have to be run again?
Stage II and stage III disease is treated with neoadjuvant chemoimmunotherapy, which is the population KEYNOTE-522 enrolled1. The evidence in Checkpoint blockade and what KEYNOTE-522 settled is confined to that population and does not extend below it.
Below stage II the evidence thins fast. The smallest node-negative tumours were excluded from the trials that define current practice, so treatment there is extrapolation from prognosis rather than from a randomised result. Node-negative triple-negative tumours with dense lymphocytic infiltration have a substantially better prognosis without chemotherapy than those without it2,3. That observation is prognostic. It has not been used prospectively to withhold treatment, and the scoring convention that makes it reproducible is in4.
What a surgery-first patient actually receives comes from a different generation of trials. It is worth seeing what they enrolled.
The randomised trials that built the adjuvant chemotherapy backbone.
Most enrolled all comers before subtype was routinely recorded, which is the population column's point.
HER2-negative early breast cancer, pT1 to pT4c, node-positive or node-negative with at least one high-risk feature.
Four cycles of epirubicin and cyclophosphamide followed by four cycles of docetaxel versus six cycles of docetaxel and cyclophosphamide.
Five-year disease-free survival was 89.6% with epirubicin and cyclophosphamide followed by docetaxel versus 89.9% with six cycles of docetaxel and cyclophosphamide. The difference was within the prespecified noninferiority margin of 4.4%.
Five-year overall survival was 94.5% with epirubicin and cyclophosphamide followed by docetaxel versus 94.7% with six cycles of docetaxel and cyclophosphamide.
Women with high-risk HER2-negative early breast cancer receiving adjuvant chemotherapy.
Six cycles of docetaxel and cyclophosphamide vs standard taxane plus anthracycline regimens.
Four-year invasive disease-free survival was 88.2% with six cycles of docetaxel and cyclophosphamide and 90.7% with taxane plus anthracycline regimens (P = .04). The hazard ratio for an invasive disease-free survival event was 1.202 (95% CI 0.97 to 1.49), above the predefined inferiority boundary of 1.18, so noninferiority could not be declared.
There was no difference in overall survival between the regimens at a median follow-up of 6.9 years.
Women with early breast cancer receiving adjuvant chemotherapy, of whom 16% were aged 65 years or older.
Four cycles of docetaxel and cyclophosphamide versus four cycles of doxorubicin and cyclophosphamide.
At a median of seven years, disease-free survival was 81% with docetaxel and cyclophosphamide versus 75% with doxorubicin and cyclophosphamide, hazard ratio 0.74, 95% CI 0.56 to 0.98, P = 0.033.
Seven-year overall survival was 87% with docetaxel and cyclophosphamide versus 82% with doxorubicin and cyclophosphamide, hazard ratio 0.69, 95% CI 0.50 to 0.97, P = 0.032.
Women with axillary lymph node-positive or high-risk lymph node-negative operable breast cancer, enrolled without regard to receptor subtype.
After doxorubicin and cyclophosphamide, paclitaxel or docetaxel, each given every 3 weeks for four cycles or weekly for 12 cycles.
Against paclitaxel every 3 weeks, the odds ratio for disease-free survival was 1.27 with weekly paclitaxel (P=0.006), 1.23 with docetaxel every 3 weeks (P=0.02) and 1.09 with weekly docetaxel (P=0.29), an odds ratio above 1 favouring the experimental schedule.
Weekly paclitaxel improved overall survival against paclitaxel every 3 weeks, odds ratio 1.32, P=0.01.
Patients with resected operable breast cancer and histologically positive axillary nodes.
Four cycles of doxorubicin and cyclophosphamide followed by four cycles of paclitaxel versus four cycles of doxorubicin and cyclophosphamide alone.
Adding paclitaxel reduced the hazard of a disease-free survival event by 17 percent (relative risk 0.83, 95 percent CI 0.72 to 0.95, P=.006), with five-year disease-free survival of 76 percent versus 72 percent.
Five-year overall survival was 85 percent in both groups (relative risk 0.93, 95 percent CI 0.78 to 1.12, P=.46), so the difference was not significant.
Women with operable breast cancer and involved axillary lymph nodes after surgical treatment.
Four cycles of doxorubicin and cyclophosphamide at three doxorubicin doses, then four cycles of paclitaxel versus no further therapy.
Adding paclitaxel after doxorubicin and cyclophosphamide reduced the hazard of recurrence by 17% (p=0.0023), with 5-year disease-free survival of 70% versus 65%. Escalating doxorubicin gave no benefit, with 5-year disease-free survival of 69%, 66% and 67% at 60, 75 and 90 mg/m2.
Five-year overall survival was 80% with paclitaxel versus 77% without, an 18% reduction in the hazard of death (p=0.0064).
node-positive operable breast cancer, all subtypes
every-2-week dose-dense chemotherapy with filgrastim vs every-3-week chemotherapy, in a 2 x 2 with sequential vs concurrent scheduling
4-year DFS 82% with dose-dense vs 75%; risk ratio 0.74, P=0.010
risk ratio 0.69, P=0.013
Only two of those rows restricted entry by receptor status. Both did so by HER2 rather than by triple-negative status. The taxane, the schedule and the anthracycline question were all settled in populations defined by nodal status and tumour size. They were applied to this subtype afterwards.
The rows agree on more than they are usually credited with. Adding a taxane after doxorubicin and cyclophosphamide lowered recurrence in both trials that tested it. Shortening the interval between cycles lowered it again in both trials that tested that. Escalating the doxorubicin dose did nothing, in the same trial that established the taxane. The backbone was therefore built by adding agents and by compressing intervals. It was never built by giving more of the same drug.
The rows that look like a disagreement are the ones about removing the anthracycline, and the disagreement is design rather than drug. US Oncology 9735 set docetaxel and cyclophosphamide against doxorubicin and cyclophosphamide, a control arm with no taxane in it8. ABC trials and WSG-PlanB set a docetaxel and cyclophosphamide regimen against a control containing both a taxane and an anthracycline6,5. Those are two different questions sharing one experimental arm. The two later trials then disagree with each other, and their noninferiority margins are not the same object either. ABC tested a hazard ratio against a fixed boundary. PlanB tested a difference in five-year disease-free survival counted in percentage points. A regimen can fail one convention and pass the other on data of the same shape.
ABC is the row the decision rests on. It enrolled HER2-negative disease specifically, it prespecified a joint analysis across three trials, and it reported early for futility with the hazard ratio above the boundary it had to clear. Noninferiority was not declared. That is why an anthracycline is still given where risk is high, and why leaving one out is a judgement rather than a result13. Dose density is where the transfer into this subtype is best supported, and Adjuvant chemotherapy regimens and dose density holds the two trials that anchor it.
What the table cannot show is a triple-negative population. Not one of these trials enrolled the subtype on its own, and the oldest of them ran before subtype was routinely recorded. Nothing here was randomised in the presence of carboplatin or of a checkpoint inhibitor, so the regimens the table settled are now the backbone underneath drugs they never met. PlanB's genomic omission rule applied to hormone receptor-positive tumours only, so the table holds no test of withholding chemotherapy on an assay in this disease.
Two things should happen at diagnosis in every patient regardless of stage.
And the neoadjuvant decision should be taken deliberately rather than by default. If the tumour is large enough or node-positive enough that residual disease would trigger a different adjuvant regimen, treating first is what makes that regimen available.
This chapter is the decision architecture and the argument. The trial record it rests on is split between two neighbours. What is given before surgery is in Neoadjuvant therapy and checkpoint blockade. What is given after it is in Adjuvant and post-neoadjuvant therapy. Where the two touch, this chapter points forward rather than restating.
2 · Immune-related toxicity in a curative-intent population
The calculation that governs immune toxicity here is not the one used in metastatic disease.
About half the patients in the control arm of KEYNOTE-522 reached a pathological complete response without pembrolizumab1. A permanent endocrinopathy in a patient who would have been cured by chemotherapy alone is a different event from the same endocrinopathy in someone with incurable disease. The trial cannot identify which patients those were, which is the whole difficulty.
What the antibody adds does not show up on the cytotoxic scale. In NSABP B-59/GeparDouze, grade 3 or higher treatment-emergent adverse events were 75.3% with atezolizumab and 73.4% with placebo14. A toxicity table built for cytotoxic drugs therefore reports the two arms as nearly the same. The events that separate them are a different class with a different natural history. In GeparNuevo, thyroid dysfunction of any grade occurred in 47% of patients15.
Three structural features of these toxicities, developed in Immune-related toxicity and its management, matter most in this setting. Onset is often delayed and is not dose-related. Reversibility differs by organ, and endocrinopathy frequently does not reverse. And the same numerical grade carries different urgency in different organs, which is why the management algorithms branch by organ16.
In practice
Hold the immunotherapy and continue the chemotherapy when an immune-related event is suspected. Those are separable decisions and treating them as one costs the patient the cytotoxic backbone that most of the curative effect came from.
Check thyroid function before every cycle. It is the commonest event and the cheapest to find15.
Steroids for a confirmed grade 2 or higher event, by the organ-specific algorithm, rather than by grade alone16.
Say before the first dose that a minority of patients acquire a permanent endocrine deficiency. Say also that about half the control arm of the defining trial cleared the tumour on chemotherapy alone1. That is the honest frame for consent in a curative setting.
Surveillance does not stop at the last dose. Events occur months after treatment ends, so the handover to primary care has to carry that instruction explicitly Rehabilitation and survivorship.
References
All 16 references
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Park JH, Jonas SF, Bataillon G, et al. Prognostic value of tumor-infiltrating lymphocytes in patients with early-stage triple-negative breast cancers (TNBC) who did not receive adjuvant chemotherapy. Ann Oncol 2019 30:1941-1949. PMID 31566659
Loi S, Drubay D, Adams S, et al. Tumor-infiltrating lymphocytes and prognosis: a pooled individual patient analysis of early-stage triple-negative breast cancers. J Clin Oncol 2019 37:559-569. PMID 30650045
Salgado R, Denkert C, Demaria S, et al. The evaluation of tumor-infiltrating lymphocytes (TILs) in breast cancer: recommendations by an International TILs Working Group 2014. Ann Oncol 2015 26:259-271. PMID 25214542
Nitz U, et al. West German Study PlanB Trial: Adjuvant Four Cycles of Epirubicin and Cyclophosphamide Plus Docetaxel Versus Six Cycles of Docetaxel and Cyclophosphamide in HER2-Negative Early Breast Cancer. J Clin Oncol 2019 37:799-808. PMID 30785826
Blum JL, et al. Anthracyclines in Early Breast Cancer: The ABC Trials-USOR 06-090, NSABP B-46-I/USOR 07132, and NSABP B-49 (NRG Oncology). J Clin Oncol 2017 35:2647-2655. PMID 28398846
Del Mastro L, De Placido S, Bruzzi P, et al. Fluorouracil and dose-dense chemotherapy in adjuvant treatment of patients with early-stage breast cancer - an open-label, 2 x 2 factorial, randomised phase 3 trial. Lancet 2015 385:1863-1872. PMID 25740286
Jones S, et al. Docetaxel With Cyclophosphamide Is Associated With an Overall Survival Benefit Compared With Doxorubicin and Cyclophosphamide: 7-Year Follow-Up of US Oncology Research Trial 9735. J Clin Oncol 2009 27:1177-83. PMID 19204201
Sparano JA, Wang M, Martino S, et al. Weekly paclitaxel in the adjuvant treatment of breast cancer. N Engl J Med 2008 358:1663-1671. PMID 18420499
Mamounas EP, et al. Paclitaxel after doxorubicin plus cyclophosphamide as adjuvant chemotherapy for node-positive breast cancer: results from NSABP B-28. J Clin Oncol 2005 23:3686-96. PMID 15897552
Henderson IC, et al. Improved outcomes from adding sequential Paclitaxel but not from escalating Doxorubicin dose in an adjuvant chemotherapy regimen for patients with node-positive primary breast cancer. J Clin Oncol 2003 21:976-83. PMID 12637460
Citron ML, Berry DA, Cirrincione C, et al. Randomized trial of dose-dense versus conventionally scheduled and sequential versus concurrent combination chemotherapy as postoperative adjuvant treatment of node-positive primary breast cancer: first report of Intergroup Trial C9741/Cancer and Leukemia Group B Trial 9741. J Clin Oncol 2003 21:1431-1439. PMID 12668651
Geyer CE, et al. Long-Term Follow-Up of the Anthracyclines in Early Breast Cancer Trials (USOR 06-090, NSABP B-46-I/USOR 07132, and NSABP B-49 [NRG Oncology]). J Clin Oncol 2024 42:1344-1349. PMID 38335467
Loibl S, Tang G, Nekljudova V, et al. Atezolizumab in early triple-negative breast cancer: the randomized phase 3 NSABP B-59/GeparDouze trial. Nat Med 2026. PMID 42680950
Loibl S, Untch M, Burchardi N, et al. A randomised phase II study investigating durvalumab in addition to an anthracycline taxane-based neoadjuvant therapy in early triple-negative breast cancer: clinical results and biomarker analysis of GeparNuevo study. Ann Oncol 2019 30:1279-1288. PMID 31095287
Schneider BJ, Naidoo J, Santomasso BD, et al. Management of immune-related adverse events in patients treated with immune checkpoint inhibitor therapy: ASCO guideline update. J Clin Oncol 2021 39:4073-4126. PMID 34724392