Table 2.

Potential application of ctDNA in clinical oncology

Cancer screening	Localized cancer	Metastatic cancer	Refractory cancer
Early diagnosis and early intervention	Identifying specific genomic alterations to guide therapeutic selection, monitoring tumor burden and therapeutic responses, detecting minimal residual disease, assessing risks of dissemination and recurrence	Early identification of relapse and treatment resistance, guidance of treatment selection, monitoring therapeutic responses	Understanding mechanism of resistance, determining new treatment