Table 1. Characteristics of studies included in the meta-analysis.
| Study | Country | Tumor type | Characteristic | Age | Gender male / female |
No. patients positive/ negative for PD-L1 | PD-L1-positive OS (%) | PD-L1-negative OS (%) | P | ||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1-yr | 3-yr | 5-yr | 1-yr | 3-yr | 5-yr | ||||||||
| Qin 2015 | China | Breast cancer | Primary | 47(21-84) | - | 189/681 | 100 | 85 | 81 | 100 | 98 | 92 | <0.001 |
| Sabatier 2015 | France | Breast cancer | Primary | ≤50: 1288 1021 (28%) 267 (31%) >50: 3207 |
- | 1076/4378 | 97 | 90 | 82 | 97 | 90 | 81 | 0.070 |
| Muenst 2014 | Switzerland | Breast cancer | Primary | 63.8 ± 14.2 | - | 152/498 | 90 | 55 | 37 | 98 | 85 | 80 | <0.001 |
| Baptista 2016 | Brazil | Breast cancer | Primary | ≤50: 176 1021 (28%) 267 (31%) >50: 204 |
107/82 | 98 | 90 | 85 | 100 | 96 | 93 | 0.030 | |
| Beckers 2016 | Australia | Breast cancer | Primary | - | - | 123/38 | 96 | 92 | 81 | 96 | 73 | 65 | 0.035 |
| Droeser 2013 | Italy | Colorectal cancer | Primary | 69.9 (30–96) | 741/673 | 669/1420 | 84 | 71 | 61 | 72 | 48 | 37 | <0.001 |
| Shi SJ 2013 | China | Colorectal cancer | Primary | 59.8 ± 12.5 | 91/116 | 64/143 | 75 | 54 | 42 | 90 | 72 | 61 | 0.017 |
| Zhu 2014 | China | Colorectal cancer | Primary | ≤50: 54 1021 (28%) 267 (31%) >50: 47 |
53/48 | 55/46 | - | - | 62 | - | - | 80 | 0.051 |
| Krambeck 2007 | USA | Renal cell carcinoma | Primary | ≤65: 54 1021 (28%) 267 (31%) >65: 47 |
150/148 | 70/228 | 78 | 62 | 48 | 91 | 83 | 76 | <0.005 |
| Thompson 2005 | Canada | Renal cell carcinoma | Primary | - | - | 103/196 | 84 | 67 | 52 | 93 | 87 | 84 | <0.001 |
| Thompson 2007 | Canada | Renal cell carcinoma | Primary | ≤65: 138 1021 (28%) 267 (31%) >65: 129 |
177/90 | 142/267 | 88 | 68 | - | 94 | 85 | - | 0.004 |
| Abbas 2016 | Germany | Renal cell carcinoma | Primary | 63 (31–88) | 116/61 | 37/140 | 85 | 57 | 47 | 92 | 75 | 66 | 0.005 |
| Choueiri 2014 | USA | Renal cell carcinoma | Primary | 59 (24–81) | 55/46 | 11/90 | 72 | 48 | 48 | 98 | 95 | 85 | <0.001 |
| Thompson 2004 | USA | Renal cell carcinoma | Primary | - | - | 87/109 | 87 | 62 | - | 95 | 92 | - | <0.001 |
| Thompson 2006 | USA | Renal cell carcinoma | Primary | - | - | 73/233 | 78 | 51 | 42 | 95 | 90 | 83 | <0.001 |
| Ohigashi 2005 | Japan | Esophageal cancer | Primary | ≤65: 24 1021 (28%) 267 (31%) >65: 17 |
32/9 | 18/41 | 60 | 18 | 18 | 88 | 53 | 45 | 0.001 |
| Tanaka 2016 | Japan | Esophageal cancer | Primary | 62.6 ± 10.0 | 157/33 | 53/127 | 61 | 30 | 25 | 79 | 56 | 51 | 0.001 |
| Chen 2014 | China | Esophageal cancer | Primary | ≤65: 51 1021 (28%) 267 (31%) >65: 48 |
76/23 | 79/20 | 100 | 44 | 17 | 83 | 44 | 37 | 0.675 |
| Loos 2011 | Germany | Esophageal cancer | Primary | - | - | 37/64 | 79 | 51 | 32 | 96 | 82 | 69 | <0.001 |
| Shohei 2016 | Japan | Gastric carcinoma | Primary | 67 ± 14 | 75/30 | 28/105 | 84 | 41 | 10 | 91 | 63 | 51 | 0.022 |
| Geng 2015 | China | Gastric carcinoma | Primary | ≤65: 65 1021 (28%) 267 (31%) >65: 35 |
61/39 | 65/100 | 72 | 41 | 29 | 87 | 61 | 37 | 0.026 |
| Hou 2014 | China | Gastric carcinoma | Primary | ≤58: 55 1021 (28%) 267 (31%) >58: 56 |
75/36 | 70/111 | 78 | 46 | 32 | 93 | 77 | 68 | <0.001 |
| Wu 2006 | Sweden | Gastric carcinoma | Primary | ≤65: 64 1021 (28%) 267 (31%) >65: 38 |
75/27 | 43/102 | 75 | 38 | 30 | 98 | 71 | 64 | 0.001 |
| Tamura 2015 | Japan | Gastric carcinoma | Primary | 66.1 (17-89) | 305/126 | 128/303 | 90 | 65 | 49 | 94 | 78 | 64 | 0.001 |
| Zheng 2014 | China | Gastric carcinoma | Primary | ≤60: 42 1021 (28%) 267 (31%) >60: 38 |
62/18 | 33/47 | 86 | 65 | 52 | 91 | 69 | 53 | 0.636 |
| Qing 2015 | USA | Gastric carcinoma | Primary | ≤60: 42 1021 (28%) 267 (31%) >60: 38 |
72/35 | 54/107 | 81 | 28 | 18 | 93 | 47 | 27 | 0.004 |
| Gao 2009 | China | Hepatocellular carcinoma | Primary | 52 (18-81) | 204/36 | 60/180 | 70 | 42 | 39 | 83 | 57 | 49 | 0.029 |
| Jung 2016 | South Korea | Hepatocellular carcinoma | Primary | ≤53: 44 1021 (28%) 267 (31%) >53: 41 |
69/16 | 23/62 | 43 | 19 | 17 | 90 | 69 | 59 | <0.001 |
| Kan 2015 | China | Hepatocellular carcinoma | Primary | ≤50: 56 1021 (28%) 267 (31%) >50: 72 |
108/20 | 105/23 | 30 | 5 | 0 | 50 | 15 | 10 | 0.001 |
| Umemoto 2015 | Japan | Hepatocellular carcinoma | Primary | 64 ± 10 | 71/9 | 37/43 | 74 | 51 | 40 | 80 | 73 | 71 | 0.051 |
| Zeng 2011 | China | Hepatocellular carcinoma | Primary | 53.1(35–68 | 109/32 | 31/32 | 38 | - | - | 85 | - | - | 0.000 |
| Gabrielson 2016 | USA | Hepatocellular carcinoma | Primary | 61 (30–86) | 50/15 | 30/35 | 85 | 85 | - | 53 | 45 | - | 0.029 |
| Wu 2009 | China | Hepatocellular carcinoma | Primary | 48, 23–75 | 65/6 | 35/36 | 81 | 54 | 40 | 97 | 83 | 71 | 0.014 |
| Azuma 2014 | Japan | Lung cancer | Primary | 66 (39-82) | 91/73 | 82/164 | - | - | 38 | - | - | 56 | 0.039 |
| Chen 2012 | China | Lung cancer | Primary | ≤54: 23 1021 (28%) 267 (31%) >54: 17 |
26/14 | 69/120 | 71 | 11 | - | 85 | 48 | - | <0.001 |
| Cooper 2015 | USA | Lung cancer | Primary | - | 477/201 | 628/678 | 95 | 73 | 62 | 84 | 54 | 44 | 0.023 |
| Jiang 2015 | China | Lung cancer | Primary | ≤60: 15 1021 (28%) 267 (31%) >60: 64 |
39/40 | 50/79 | 100 | 91 | 84 | 83 | 74 | 70 | 0.042 |
| Kim 2015 | South Korea | Lung cancer | Primary | 65 (45–81) | 33/8 | 89/331 | 65 | 38 | 27 | 78 | 49 | 49 | 0.570 |
| Mu 2011 | China | Lung cancer | Primary | - | - | 58/109 | 87 | 20 | - | 95 | 38 | - | <0.005 |
| Velcheti 2014 | USA | Lung cancer | Primary | ≤70: 232 1021 (28%) 267 (31%) >70: 80 |
260/37 | 56/155 | 78 | 43 | 27 | 87 | 61 | 51 | 0.028 |
| Yang 2014 | Taiwan | Lung cancer | Primary | ≤70: 132 1021 (28%) 267 (31%) >70: 31 |
54/109 | 65/163 | 98 | 93 | 91 | 98 | 87 | 83 | 0.027 |
| Zhang 2014 | China | Lung cancer | Primary | ≤58: 73 1021 (28%) 267 (31%) >58: 70 |
84/59 | 70/143 | 84 | 71 | 53 | 97 | 89 | 77 | 0.002 |
| Song 2016 | China | Lung cancer | Primary | <60: 207 ≥60: 178 |
198/187 | 186/199 | 99 | 71 | 40 | 99 | 79 | 52 | 0.069 |
| Inamura 2016 | Japan | Lung cancer | Primary | <60: 96 ≥60: 172 |
142/126 | 43/225 | 85 | 69 | 55 | 95 | 81 | 71 | 0.019 |
| Chen 2009 | China | Pancreatic cancer | Primary | <60: 61 ≥60: 55 |
76/23 | 18/40 | 32 | 8 | - | 84 | 58 | 17 | 0.001 |
| Nomi 2007 | Japan | Pancreatic cancer | Primary | - | - | 20/51 | 48 | 12 | - | 78 | 24 | - | 0.016 |
| Wang 2010 | China | Pancreatic cancer | Primary | - | 40/10 | 23/40 | 87 | 8 | - | 100 | 33 | - | <0.001 |
| Gadiot 2011 | Netherlands | Merkel cell carcinoma | Primary | - | 36/27 | 16/63 | - | 51 | 37 | - | 68 | 52 | 0.200 |
| Hino 2010 | Japan | Merkel cell carcinoma | Primary | 68.84 ± 2.85 | 38/21 | 34/59 | - | - | 52 | - | - | 81 | 0.040 |
| Taube 2012 | USA | Merkel cell carcinoma | Primary | - | 76/74 | 57/150 | - | - | 84 | - | - | 61 | 0.330 |
| Boorjian 2008 | USA | Urinary tract epithelial cell carcinoma | Primary | - | 259/59 | 39/314 | 58 | 51 | 43 | 91 | 82 | 67 | 0.005 |
| Nakanishi 2006 | Japan | Urinary tract epithelial cell carcinoma | Primary | - | 47/18 | 46/65 | 86 | 68 | 57 | 100 | 100 | 100 | 0.021 |
| Wang 2009 | China | Urinary tract epithelial cell carcinoma | Primary | - | 31/5 | 36/50 | 91 | 68 | - | 100 | 100 | - | 0.020 |
| Xylinas 2014 | USA | Urinary tract epithelial cell carcinoma | Primary | 65.9 (60.5e72.2) | 244/58 | 76/226 | 83 | 66 | 63 | 95 | 82 | 69 | 0.020 |
| Kim 2016 | South Korea | Oral squamous cell cancer | Primary | 65 (45–81) | 33/8 | 90/43 | 97 | 83 | 80 | 98 | 83 | 75 | 0.625 |
| Lin 2015 | Taiwan | Oral squamous cell cancer | Primary | <56: 162 ≥56: 143 |
236/69 | 133/172 | 81 | 62 | 56 | 81 | 62 | 58 | 0.225 |
| Cho 2011 | South Korea | Oral squamous cell cancer | Primary | <59: 20 ≥59: 25 |
32/13 | 26/45 | 72 | 51 | 43 | 72 | 63 | 63 | 0.012 |
| Oliveira 2015 | USA | Oral squamous cell cancer | Primary | <60: 62 ≥60: 34 |
85/11 | 47/96 | 81 | 47 | - | 61 | 18 | - | 0.044 |
| Ukpo 2013 | USA | Oral squamous cell cancer | Primary | 55.8 ± 9.4 | 186/23 | 84/181 | 89 | 74 | 62 | 97 | 76 | 64 | 0.730 |