Clinical Summary:

• Design/Population: Pooled analysis of the WSG PlanB and ADAPT trials evaluating chemotherapy strategies in patients with high-risk HR-positive, HER2-negative early breast cancer, including those with recurrence scores >25 or ≥4 positive lymph nodes.
• Key Outcomes: No significant differences were observed between neoadjuvant and adjuvant chemotherapy or between anthracycline-containing and anthracycline-free regimens. Longer docetaxel-based combination chemotherapy was associated with improved outcomes compared with shorter dose-dense taxane-based treatment.
• Clinical Relevance: These findings provide insight into chemotherapy selection for high-risk HR-positive breast cancer and suggest a potential benefit for longer docetaxel-based regimens, although interpretation should consider the retrospective pooled design and evolving treatment landscape.

Oleg Gluz, MD, discusses results from a pooled analysis of the PlanB and ADAPT trials examining optimal chemotherapy strategies in patients with high-risk HR-positive, HER2-negative early breast cancer.

The analysis found no apparent differences in outcomes based on neoadjuvant versus adjuvant treatment timing or anthracycline use. However, patients treated with longer docetaxel-based combination chemotherapy experienced improved outcomes compared with those receiving shorter dose-dense taxane-based regimens, suggesting that treatment duration and regimen composition may influence long-term benefit in this high-risk population.

Dr Gluz presented these results at the 2026 ASCO Annual Meeting in Chicago, Illinois.

Transcript: 

My name is Oleg Gluz, I am one of the scientific directors of the West German Study Group, and today I am presenting results from a pooled analysis of the WSG ADAPT and PlanB trials in patients with high-risk, early hormone receptor-positive, HER2-negative breast cancer.

There is still some uncertainty regarding the optimal chemotherapy approach in patients with a recurrence score >25 or in patients with >4 positive lymph nodes. Questions remain about whether to use neoadjuvant or adjuvant chemotherapy, whether to use dose-dense or non–dose-dense chemotherapy, and whether docetaxel-based or paclitaxel-based regimens are preferable. Therefore, we pooled data from 2 trials that tested different chemotherapy schedules.

PlanB evaluated 6 cycles of docetaxel plus cyclophosphamide given every 3 weeks compared with 4 cycles of epirubicin and cyclophosphamide followed by 4 cycles of docetaxel. The ADAPT trial evaluated monotherapy with dose-dense paclitaxel or nab-paclitaxel given for 8weeks, followed by 4 cycles of dose-dense EC. In both trials, all patients with a recurrence score >25 or with >4 positive lymph nodes received chemotherapy. We then pooled the data and observed 3 clinically important findings.

The first was that we did not observe any difference between neoadjuvant and adjuvant chemotherapy, which in the ADAPT trial was chosen at the investigator’s discretion. Outcomes after 5 years were essentially the same. Second, we looked at the very controversial topic of anthracycline use versus anthracycline-free chemotherapy in this pooled analysis. We did not observe any difference related to anthracycline use. However, it is important to note that in a previous pooled analysis that included the SUCCESS trial in Germany, we did observe some benefit from anthracyclines in patients with more than four positive lymph nodes, consistent with findings reported from US studies.

The third finding, and probably the most interesting part of this analysis, was the comparison between longer docetaxel-based treatment delivered as combination therapy from the beginning versus the shorter 16-week dose-dense treatment approach in this high-risk population. Here, we observed a benefit in favor of the longer docetaxel-based regimen, which also involved combination treatment from the beginning. These findings may have implications for clinical practice worldwide.

Of course, these results should be interpreted with caution because they are based on cross-trial comparisons. They also need to be considered in the context of modern endocrine-based treatment strategies, since these trials were conducted in Germany between 2009 and 2018, before CDK4/6 inhibitors were incorporated into routine practice. 

Nevertheless, these findings provide important insights for everyday clinical decision-making in patients with high-risk, hormone receptor-positive, HER2-negative early breast cancer.

Source: 

Gluz O, Kuemmel S, Nitz U, et al. Role of neoadjuvant versus adjuvant chemotherapy, dose density, and treatment schedule in biologically high-risk HR+/HER2- breast cancer: A pooled analysis of the WSG ADAPT-HR+/HER2- and PlanB trials. Presented at the ASCO Annual Meeting. May 29 - June 2, 2026. Chicago, Illinois. Abstract LBA515.