Eline Verreck BSc; 2026 EBCC: Radiation Boost May No Longer Be Justified After Standard Therapy for Early Breast Cancer

Radiation Boost May No Longer Be Justified After Standard Therapy for Early Breast Cancer

An interview with:

Eline Verreck BSc, Erasmus University Medical Centre, Surgical Oncology Department, Rotterdam, The Netherlands

BARCELONA, Spain—Any benefit from an additional tumor-bed radiotherapy “boost” after completing standard therapy for early breast cancer seems no longer to be justified in this age of increasingly effective systemic treatments now being incorporated into standard breast-conserving therapy. A new study conducted in the Netherlands, with 34,504 patients followed up for a median of 8.3 years, has found that the possible small reductions of long-term local recurrence rates from using a boost no longer justify the toxicities such a boost can bring.

Findings were reported at the 2026 meeting of the European Breast Cancer Conference by Eline Verreck BSc, who is a PhD candidate at Erasmus University Medical Centre’s Department of Surgical Oncology in Rotterdam.  She talked about her results with the Audio Journal of Oncology’s correspondent, Peter Goodwin:

AUDIO J0URNAL OF ONCOLOGY: Eline Verreck BSc

IN:  [GOODWIN]” Welcome to more news here from the …..

OUT: …….I’m Peter Goodwin for the Audio Journal of Oncology 7:00secs

EBCC 2026 ABSTRACT PPT-054

“The relevance of a boost in the current era of systemic therapy after breast-conserving surgery and radiotherapy”

Verreck1,, W.D. Heemsbergen2,, T. van Dalen3,, S. Windhorst4,, L. de Munck4,, F. van der Leij5,, L.J. Boersma6,, F.E. Froklage2,.

1Erasmus University Medical Centre, Surgical Oncology, Rotterdam, The Netherlands.

2Erasmus University Medical Centre, Department of Radiation Oncology, Rotterdam, The Netherlands.

3Erasmus University Medical Centre, Department of Surgical Oncology, Rotterdam, The Netherlands.

4Netherlands Comprehensive Cancer Organisation, Department of Research and Development, Utrecht, The Netherlands.

5University Medical Centre Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands.

6Grow Research Institute for Oncology and Reproduction- Maastricht University Medical Centre+, Department of Radiation Oncology Maastro, Maastricht, The Netherlands.

Background:

Breast-conserving surgery (BCS) is commonly followed by whole breast radiotherapy (WBRT), which may include a boost to the tumour bed. The former boost trial (Bartelink, 2015) showed a 50% reduction in local recurrence (LR) risk. However, systemic therapy has evolved substantially since then, resulting in an absolute LR risk of <5% at 10 years. In the current era, a boost may therefore represent overtreatment. Moreover, it is associated with increased fibrosis risk and poorer cosmetic outcomes. The Assisi Think Tank Meeting 2024 suggested omission of a boost in patients whose 10-year LR risk without a boost is <6%. Therefore, this study aims to identify patients with a 10-year LR risk of <6% after WBRT without a boost, and patients with a 10-year LR risk of <3% after WBRT with a boost.

Methods:

This study included all Dutch breast cancer (BC) patients treated with BCS and adjuvant WBRT between 2012-2016. Data were obtained from the Netherlands Cancer Registry, and information on LR was collected through linkage with PALGA, the nationwide pathology database. Using this methodology, LR data completeness is estimated to be approximately 80% (van Maaren, 2025). The LR risk was described for patients treated without and with boost, and for subgroups defined by known risk factors within these two categories.

Results:

A total of 34,504 patients with a median follow-up of 8.3 years were included. Four percent were ≤40 years old, 23% had grade 3 tumours, 11% had triple-negative BC, and 6% had focally positive margins, with 90%, 82%, 75%, and 87% of each group receiving a boost, respectively. (Neo)adjuvant systemic therapy was administered to 64% of patients (39% chemotherapy +/- targeted therapy, 52% endocrine therapy). LR occurred in 343 patients (1.0%), of whom 174 (51%) had solitary LR, and 169 (49%) also developed regional recurrence and/or distant metastases. Among 15,953 patients who did not receive a boost, 0.9% developed LR, and among 17,321 patients who received a boost, 1.1% developed LR. In all subgroups, the 8.3-year LR rate was below 6% (without boost) and 3% (with boost) (Table 1), even after adjusting for 80% completeness.

Conclusions: 

The LR rate in BC patients treated with BCS and WBRT was 1.0% at a median follow-up of 8.3 years. In subgroups of patients treated without or with boost, LR rates did not exceed 6% and 3%. These findings hypothesize that, when patients are categorized by univariable risk factors, a boost may no longer be clinically relevant in the modern systemic therapy era.

https://www.ejcancer.com/article/S0959-8049(26)00084-5/abstract

Eline Verreck 2026 EBCC Audio Journal of Oncology Text