SABR in oligometastatic breast cancer: Current status and future directions

Oligometastatic breast cancer (OMBC) is a heterogeneous disease with intrinsic biological diversity. It is increasingly accepted in clinical practice that patients with OMBC could be treated with the expectation of long-term disease remission. Local ablative treatments, such as radiotherapy or surgery have a role in this setting. At present, patients that may benefit are characterised by low tumour burden, long diseasefree interval and the capacity to completely ablate all sites of disease. In the future, biological or genomic classifiers may help predict which patients may benefit the most from local ablative treatments. This review provides an overview of the proposed classifications of oligometastatic disease and outlines the standard systemic treatment options of endocrine therapy, chemotherapy, and immunotherapy. The evidence for localized treatment with stereotactic ablative body radiotherapy (SABR) is presented. We discuss current active trials in oligometastatic cancer and discuss potential future directions for the use of SABR in the treatment of OMBC. (c) 2021 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Oligometastatic breast cancer is a heterogeneous disease with intrinsic biological diversity. The review discusses treatment options, classifications, and potential future directions, emphasizing the role of local ablative treatments and systemic therapies. It also suggests the use of biological or genomic classifiers for predicting treatment benefits in the future.