Table 6. Characteristics of included studies.

ctDNA, circulating tumor DNA; OS, overall survival; MCED, multi-cancer early detection; TEC-Seq, targeted error correction sequencing

Author of the Study	Year of Publication	Type of Publication	Aim of the Study	Conclusion
Dang DK et al. [26]	2022	Traditional review	To determine the role of ctDNA as a cancer screening tool	CtDNA could be better used as a supplemental tool, which could help guide the management of tumors and their prognosis
IA Cree et al. [33]	2017	Systematic review	To identify a blood-based tumor marker for non-invasive cancer detection	ctDNA has the potential to be considered as a potential biomarker for cancer detection in future
JD Merker et al. [34]	2018	Systematic review	Utility of ctDNA in solid tumors	No strong evidence is available on the utility of ctNA in clinical practice.
Ocana A et al. [35]	2016	Systematic review	Association between ctDNA and overall survival in solid tumors	Positive ctDNA assay is associated with worse outcomes
X Chen et al. [36]	2021	Case-control study	To determine OS in patients who tested positive for MCED study	The outcome of patients with negative MCED was better when compared to those with a positive MCED
X Chen et al. [37]	2020	Longitudinal study	Detection of ctDNA using PanSeer, a non-invasive blood test four years before conventional tumor diagnosis	PanSeer could successfully detect cancer in asymptomatic individuals four years earlier than standard screening or diagnostic techniques
Schwaederle M et al. [38]	2016	Cross-sectional study	The ability of ctDNA to detect tumor mutations and its concordance with tissue biopsies	The ability of ctDNA to determine treatment and prognosis
J Phallen et al. [39]	2017	Clinical evaluation study	Evaluating the ability of the TEC-Seq technique to detect cfDNA	The test is useful in detecting early-stage cancers and assists in determining prognosis
JD Cohen et al. [40]	2018	Clinical evaluation study	Evaluating the ability of CancerSEEK, a multi-analyte blood test in tumor detection	CancerSEEK was successful in identifying and locating the majority of the tumors
C Fiala et al. [41]	2018	Traditional review	Applications of ctDNA in different aspects of cancer management focusing on early cancer detection	The sensitivity and specificity of ctDNA in tumor detection are fairly low and are not advisable to implement at the level of clinical practice
M Scarlotta et al. [42]	2019	Traditional review	Applications of the biomarkers - ctDNA, tumor cells, extracellular vesicles in the management of tumor	All three techniques showed promising results, while ctDNA was superior
AH Ren et al. [43]	2020	Traditional Review	Limitations of ctDNA as a tumor marker	The limitations of ctDNA are high enough to prompt further research for its implementation in routine care