Correlation between RASSF1A Methylation in Cell-Free DNA and the Prognosis of Cancer Patients: A Systematic Review and Meta-Analysis

Table 2

Quality assessment of the included studies.

Study	Representativeness of the exposed cohort	Selection of the unexposed cohort	Ascertainment of exposure	Outcome of interest not present at start of study	Control for important factor or additional factor	Outcome assessment	Follow-up long enough for outcomes to occur	Adequacy of follow-up of cohorts	Total quality scores
Balgkouranidou et al. [13]	☆	☆	☆	—	—	☆	☆	☆	6
Fiegl et al. [14]	☆	☆	☆	☆	—	☆	☆	☆	7
Gӧbel, et al. [17]	☆	☆	☆	☆	☆	☆	☆	☆	8
Karamitrousis et al. [16]	☆	☆	☆	—	—	☆	☆	☆	6
Matthaios et al. [15]	☆	☆	☆	—	—	☆	☆	☆	6
Pimson et al. [23]	☆	☆	☆	—	☆	☆	☆	☆	7
Rasmussen et al. [24]	☆	☆	☆	—	☆☆	☆	☆	☆	8
Saliminejad et al. [25]	☆	☆	☆	—	—	☆	☆	☆	6
Zavridou et al. [26]	☆	☆	☆	☆	—	☆	☆	☆	7