“…Of the 42 articles selected for the review [ 8 , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] , [30] , [31] , [32] , [33] , [34] , [35] , [36] , [37] , [38] , [39] , [40] , [41] , [42] , [43] , [44] , [45] , [46] , [47] , [48] , [49] , [50] , [51] ], 24 studies considered NLR, eight studies PLR, and 10 studies both NLR and PLR. Moreover, 40 studies were retrospective and only two were prospective, either mono- or multi-center clinical trials ( Supplementary tables 2, 3, 4 and 5 ).…”