Circulating Tumour DNA in Muscle-Invasive Bladder Cancer

Circulating tumour DNA (ctDNA) is an attractive tool in cancer research, offering many advantages over tissue samples obtained using traditional biopsy methods. There has been increasing interest in its application to muscle-invasive bladder cancer (MIBC), which is recognised to be a heterogeneous disease with overall poor prognosis. Using a range of platforms, studies have shown that ctDNA is detectable in MIBC and may be a useful biomarker in monitoring disease status and guiding treatment decisions in MIBC patients. Currently, with no such predictive or prognostic biomarkers in clinical practice to guide treatment strategy, there is a real unmet need for a personalised medicine approach in MIBC, and ctDNA offers an exciting avenue through which to pursue this goal. In this article, we present an overview of work to date on ctDNA in MIBC, and discuss the inherent challenges present as well as the potential future clinical applications.