TAC chemotherapy improves relapse-free survival in certain early breast cancer subtypesDoctors found that certain tumor markers might help choose the best cancer treatment plan for some patients

Breast (Edinburgh, Scotland) Published June 1, 2026 Study authors: Opdam Mark, Ultee Nigel, Geenen Jill J J, van Rossum Annelot G J, Mandjes Ingrid A M, Balduzzi Sara,… PubMed ↗ DOI ↗ Editorial oversight: Dr. Sofia Müller, MD · Lifespan & Whole-Person Care

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Key Takeaway

Consider that TAC may benefit specific early breast cancer subtypes, but biomarker guidance remains investigational.

A randomized controlled trial in patients with early breast cancer compared the TAC regimen (docetaxel, doxorubicin, cyclophosphamide) to a dose-dense schedule of doxorubicin and cyclophosphamide. The study focused on relapse-free survival in molecular subtypes, including TN EZH2 and TUBB tumors.

The trial reported improved relapse-free survival for TAC in TN EZH2 tumors and for TUBB tumors when adjusted for stromal tumor-infiltrating lymphocytes. The authors noted that the comparator ddAC also showed improved survival in these subtypes, but with different effect sizes. The study identified potential biomarkers linked to taxane response, though none are in clinical use.

Key limitations include the small cohort sizes for specific biomarker subgroups and the need for further research with more patients to confirm these findings. The authors caution that high tubulin expression may predict docetaxel benefit only when adjusted for sTILs, and that biomarker-guided therapy remains investigational.

Clinically, the results suggest that certain molecular features may help select patients for TAC, but the evidence is not yet sufficient to change practice. Restraint is warranted until larger studies validate these associations.

Researchers studied 664 patients who had early stage breast cancer. They compared two main treatment groups. One group received a mix of three drugs called TAC. The other group got a faster schedule of two drugs called ddAC. The goal was to see which plan kept the cancer from returning or spreading better.

Scientists looked closely at specific parts of the cancer cells to find patterns. They found that some tumors responded very well to the three-drug plan. In these cases, the chance of the cancer returning was much lower. Other tumors did better with the two-drug plan, especially when cell markers were checked first.

The team noted that knowing more about the cancer cells helps make smarter choices. However, they said they need to study more people to be sure. This research helps doctors understand how to match the right medicine to the right patient.

What this means for you:

Specific tumor features may help doctors choose the best drug plan to stop breast cancer from returning.

Study Details

Study typeRct

Sample sizen = 664

EvidenceLevel 2

PublishedJun 2026

PMID41864056

View Original Abstract ↓

BACKGROUND: Intensified anthracycline-based regimens are as effective as standard anthracycline-based chemotherapy with taxanes in unselected high-risk patients with early breast cancer and come with their own toxicity profiles. Many biomarkers linked to taxane resistance have been identified, but none are used clinically. A predictive biomarker for taxane resistance or sensitivity would help personalise treatment. METHODS: In the randomised controlled trial MATADOR (ISRCTN61893718), 664 patients with pT1-3, pN0-3 breast cancer were treated with either docetaxel, doxorubicin, and cyclophosphamide (TAC) or dose-dense schedule of doxorubicin and cyclophosphamide (ddAC). IHC protocols for 13 previously proposed biomarkers (ABCB1, AR, BCL2, CyclinD1, EZH2, GSTP1, pH2AX, Ki67, MAPT, P53, Thioredoxin, TUBB, and TUBB3) were tested in all 577 clinical high-risk patients. The prognostic and predictive value was assessed in the total group, and in the hormone receptor-positive HER2-negative and in the triple-negative (TN) subgroup. RESULTS: Patients with TN EZH2 tumours have improved RFS after TAC treatment (n = 83 adjusted hazard ratio [adjHR] 0.35 [0.14-0.83]), while with EZH2 RFS improved after ddAC (n = 16 adjHR 6.31 [0.79-50.5]; P0.01). Similar findings are observed for TUBB when stromal tumour-infiltrating lymphocytes (sTILs) are included in the model. TUBB have improved outcome after TAC treatment (n = 48 adjHR 0.26 [0.08-0.80]), while for TUBB improved with ddAC (n = 47 adjHR 1.94 [0.58-6.50]; P0.03). CONCLUSIONS: Patients with TN EZH2 tumours benefit more from ddAC, while EZH2 have a better outcome after TAC. High tubulin expression may predict docetaxel benefit if adjusted for sTILs. Further research with more patients is needed to find the best use of these biomarkers. CLINICAL TRIAL IDENTIFICATION: MATADOR, ISRCTN61893718, BOOG 2005-02, CKTO 2004-04.

TAC chemotherapy improves relapse-free survival in certain early breast cancer subtypesDoctors found that certain tumor markers might help choose the best cancer treatment plan for some patients

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