Benefits and limitations of ctDNA-based technology for the assessment of immunotherapy response
| Benefits | Limitations |
| Reduction in ctDNA levels associated with overall survival and progression-free survival | Comorbidities can affect ctDNA levels (smoking, pregnancy, heart disease, inflammation) |
| Detection of immunotherapy response after about 8 weeks | Clonal hematopoiesis |
| Allows for serial monitoring to detect developing resistance and genomic variants | Variable ctDNA fraction based on primary malignancy and stage |
| Non-invasive detection (blood test) | Multiple assays to choose from with no standardization |
| Comprehensive, patient-specific molecular profiling | Wide variability in cost |
| - | Concordance between aberrations detected in ctDNA and tumor tissue |
| - | Low concentration and fragmentation |
| - | Unable to detect genomic fusion events and copy number changes |
ctDNA: circulating tumor DNA; -: no data