Clinical Impact of Somatic Genomic Testing on Breast Cancer Care

Abstract

Developments in our understanding of the molecular biology of breast cancer have had a direct impact on the investigations needed to provide optimal breast cancer care. Somatic genomic tests are now used routinely to inform decisions regarding adjuvant chemotherapy use in selected early breast cancer patients, and to identify patients with advanced disease who can potentially benefit from novel targeted agents.

In this overview, we describe the somatic genomic tests currently available within the National Health Service (NHS) for early and advanced breast cancer patients. We review the underlying biology and the evidence base for clinical utility of these tests in routine clinical practice. In addition, we identify the somatic genomic biomarkers currently in use in breast cancer clinical trials that are most likely to influence future breast cancer management. We also consider the challenges associated with tissue-based genomic testing in advanced breast cancer and the role of circulating tumour deoxyribonucleic acid (ctDNA) testing.