“…After elimination of duplicates and screening of the titles and abstracts of each of the articles, 18 were selected as potentially eligible for full-text reading. Ten articles were excluded, three of them for not containing valid data [ 44 , 45 , 46 ], another three because they were poster or abstract [ 47 , 48 ], three because of a lack of a control group [ 19 , 20 , 49 , 50 ], and one for including patients without cancer [ 51 ] (provided in Supplementary Table S1 ). Finally, eight studies [ 39 , 40 , 41 , 42 , 52 , 53 , 54 , 55 ] were selected for the meta-analysis.…”