“…The diagnostic criteria of advanced cancer were presented in 13 studies (13/50), with five studies [ 6 , 30 , 31 , 60 , 61 ] adopting the criteria of cancer with metastasis, and seven studies [ 9 , 41 , 42 , 45 , 58 , 63 , 75 ] using the stage III/IV criterion according to TNM staging system. With regards to geographic distribution, nine studies were conducted in the USA [ 38 , 40 , 46 , 49 , 52 , 57 , 59 , 70 , 74 ], seven were in mainland China (six of which were conducted in Shanghai) [ 9 , 53 , 63 – 67 ], five in Australia [ 6 , 54 , 55 , 60 , 68 ], five in the Netherlands [ 29 – 31 , 34 , 44 ], four in Canada [ 47 , 50 , 56 , 73 ], three in Japan [ 33 , 39 , 41 ], three in Taiwan [ 35 , 42 , 62 ], two in the UK [ 69 , 71 ], two in Denmark [ 45 , 72 ], two in Hong Kong [ 58 , 75 ], and one each in Italy [ 28 ], France [ 61 ], South Korea [ 32 ], Spain [ 37 ], Indonesia [ 36 ], Czech Republic [ 43 ], India [ 51 ], and Bangladesh [ 48 ]. Characteristics and main findings of all included studies are presented in Table 2 ...…”