Evaluation of the Role of Stereotactic Body Radiotherapy (SBRT) in Advanced Breast Cancer
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Embargo End Date
2026-05-12
ICR Authors
Authors
Nagpal, S
Document Type
Thesis or Dissertation
Date
2025-11-12
Date Accepted
Abstract
Background: Stereotactic body radiotherapy (SBRT) delivers excellent local control (LC) with minimal toxicity in oligometastatic breast cancer (OMBC). However, randomised controlled trials have produced conflicting survival outcomes, leaving uncertainty about which patients benefit most from SBRT. This thesis evaluates the role of SBRT in OMBC and aims to identify the subgroups most likely to benefit. Methods: A retrospective analysis compares 10-year outcomes of metachronous versus synchronous OMBC treated with SBRT. The PERSPECTIVE study explores patients’ perspectives on SBRT for OMBC, while an international survey explores clinicians’ perspectives. The utility of Contrast Clearance Analysis (CCA) MRI was evaluated in distinguishing treatment effects from active brain metastases post-SRS, where standard contrast-enhanced MRI findings were equivocal. The TRAK-ER SBRT sub-study investigates circulating tumour DNA (ctDNA) changes before and after SBRT and the risk of early disease progression in OMBC. It also investigates whether whole-body MRI (WBMRI) detects further metastases compared to standard imaging. Results: SBRT offers 2-year LC rates of over 85%, comparable for synchronous and metachronous OMBC. In the PERSPECTIVE study, patients prioritised extension of life but would consider SBRT for its LC and durable pain relief benefits. The clinician survey demonstrates that most clinicians consider SBRT for the treatment of metachronous and synchronous OMBC and highlight LC as a key future trial endpoint. CCA appears to add value to standard contrast-enhanced MRI for distinguishing treatment-related effects from active disease. The ongoing TRAK-ER SBRT sub-study has opened to recruitment in the UK and France.Conclusions: SBRT provides excellent LC for synchronous and metachronous OMBC. Patients and clinicians support the use of SBRT for OMBC and consistently rate LC as a key priority. CCA offers additional diagnostic value in differentiating treatment effects from active disease post-SRS. The TRAK-ER sub-study aims to provide insights into the role of ctDNA analysis and WBMRI in identifying OMBC patients most likely to benefit from SBRT.
Citation
2025
DOI
Source Title
Publisher
Institute of Cancer Research (University Of London)
ISSN
eISSN
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Research Team
Uro-oncology Trials