Liquid biopsy for brain metastases and leptomeningeal disease in patients with breast cancer

A significant subset of patients with metastatic breast cancer develops brain metastasis. As efficacy of systemic therapies has improved and patients live longer with metastatic breast cancer, the incidence of breast cancer brain metastases has increased. Brain metastases pose a clinical challenge in diagnosis, treatment, and monitoring across all breast cancer subtypes, and better tools are needed. Liquid biopsy, which enables minimally invasive sampling of a patient's cancer, has the potential to shed light on intra-cranial tumor biology and to improve patient care by enabling therapy tailoring. Here we review current evidence for the clinical validity of liquid biopsy in patients with breast cancer brain metastases, with a focus on circulating tumor cells and circulating tumor DNA.

Automated summary

A subset of metastatic breast cancer patients develop brain metastasis, and as systemic therapies have improved, the incidence of breast cancer brain metastases has increased. Brain metastases pose challenges in diagnosis, treatment, and monitoring in all subtypes of breast cancer, and liquid biopsy offers a potential solution. This review focuses on the clinical validity of liquid biopsy, specifically circulating tumor cells and circulating tumor DNA, in patients with breast cancer brain metastases.