Presented during the ESTRO 2026 session “Highlights: Latest Trials – Breast” by Professor David Krug, new data from OLIGOMA trial suggest that targeted radiotherapy may help prolong disease control in selected patients with breast cancer that has begun to spread.
The study focused on oligometastatic breast cancer, a setting in which a small number of metastatic lesions have developed outside the primary tumor site. These patients are usually treated with systemic therapy, such as chemotherapy and/or hormone therapy, similar to patients with more advanced metastatic disease. However, the role of adding local treatment to all visible metastatic lesions has remained uncertain in breast cancer.
Study Rationale
Stereotactic body radiotherapy, or SBRT, is a highly precise form of radiotherapy that delivers high doses of radiation directly to tumor lesions while limiting exposure to surrounding healthy tissue. Although SBRT is already used in several cancer types, its benefit in oligometastatic breast cancer has been less clear.
Professor Krug noted that while SBRT is known to be an effective local treatment, there has been limited evidence showing that it can improve broader outcomes such as progression-free survival in oligometastatic breast cancer.
Methods
The randomized controlled trial included 87 patients treated across 31 hospitals in Germany and Austria between March 2021 and April 2024. Each patient had one to five small metastatic lesions.
Patients were divided into two groups. One group received standard systemic treatment, including chemotherapy and/or hormone therapy. The other group received the same standard treatment plus SBRT directed at each metastatic lesion. Researchers then followed patients to assess survival, disease progression, and quality of life after treatment.
Key Results
Patients who received SBRT to their metastatic lesions lived longer without their cancer worsening. Median progression-free survival was 36.2 months in the SBRT group, compared with 20.6 months in the standard-treatment group. According to the study report, this corresponded to approximately a halving of the risk of cancer progression or death.
Importantly, quality-of-life outcomes were similar between the two groups. The average deterioration in the radiotherapy group was around two points on a 0–100 scale, well below the predefined margin of ten points.
Interpretation
These findings suggest that adding metastasis-directed SBRT to standard systemic therapy may help delay disease progression in selected patients with oligometastatic breast cancer, without a major negative effect on quality of life.
However, the trial was smaller than planned and was stopped early because of slow recruitment. Professor Krug explained that some patients were not eligible because they had too many metastatic lesions by the time spread was detected, while others preferred to receive radiotherapy outside the trial rather than risk being assigned to standard treatment alone.
Conclusion
The study adds encouraging evidence for the use of targeted radiotherapy in carefully selected patients with oligometastatic breast cancer. While further clinical trial results are needed, the data support continued investigation of SBRT as part of a more individualized treatment strategy for breast cancer that has begun to spread.
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