Circulating tumor DNA for breast cancer: Review of active clinical trials

•Research studies are currently investigating biomarkers for early detection of breast cancer.•Interventional liquid biopsy aims at guiding choice of therapy and treatment modifications.•Active clinical trials show how liquid biopsy is being utilized and its clinical implications.•Circulating tumor DNA has been used to detect tumor burden and minimal residual disease in metastatic breast cancer.•There are multiple uses of ctDNA that can help physicians in early detection and treatment of localized breast cancer and.