Minimal Residual Disease in Metastatic Soft Tissue Sarcoma.

opinion statementLiquid biopsies represent a promising and minimally invasive approach to diagnosing and monitoring cancer. In recent years, studies across a multitude of solid organ malignancies have suggested the clinical utility of biomarkers such as circulating tumor DNA (ctDNA). Particular attention has been given to serial assessment of such biomarkers in an effort to detect minimal residual disease (MRD), in order to predict which patients may be at highest risk of relapse following curative-intent surgical or medical intervention. Such investigations are particularly relevant to sarcomas, which are highly heterogeneous malignancies and commonly develop treatment resistance. While preliminary research described herein is promising, there remain key barriers to widespread adoption of liquid biopsy in sarcoma, including the lack of standardized detection methods, high cost, and the need for large, prospective studies to validate their clinical utility. Given the high level of interest in liquid biopsy in the biomedical community, it is plausible such obstacles may be overcome in the near future. With such advancements, one can anticipate that liquid biopsies may become a key tool in the sarcoma oncologists armamentarium, and offer a path toward improved outcomes for patients with sarcoma.