Table 1.
Characteristics of the studies included in the meta-analysis.
| Study cohort | Year | Country | N | Age (yrs; median and range) | Type of study | PD-L1 Antibody used | PD-L1+(%) | Detection standard | Study end-points | HR | Follow-up, median in months | NOS score |
| António Polónia | 2017 | Spain | 440 | 60.0(28–92) | Retrospective | clone SP142(R) | 28 (6.4%) | membranous/cytopl-asmic staining≥1% | OS | R (M) | 120 (1–120) | 6 |
| Xiaoxian Li | 2016 | USA | 136 | NA | Retrospective | clone NAT105 (M) | 14 (10.3%) | H-score≥5 | OS/DFS | R (M) | 36-144 | 6 |
| Julia Y. S. Tsang | 2017 | China | 1091 | 54.5 ± 12.7 (22–94) | Retrospective | NA | 295 (27.0%) | Mean immunoscore (staining intensity) | OS/DFS | R (M) | 63 (1–210) | 7 |
| Jing He | 2018 | USA | 68 | 48.0 (23–75) | Retrospective | clone 28–8 (R) | 25 (36.8%) | Mean immunoscore (staining intensity) | OS/DFS | R (M/U) | 48 (23–75) | 8 |
| Ming Li | 2018 | China | 101 | 51 (27–74) | Retrospective | CST, 13,684 (R) | 39 (38.61%) | H-score≥5 | DFS | R (M/U) | 49.03 (10.97–94.27) | 7 |
| Hitomi Mori | 2017 | Japan | 284 | 59.6 | Retrospective | E1L3N (R) | 103 (41.5%) | PD-L1 expression≥50% | OS/RFS | R (M/U) | 68 (2–150) | 6 |
| Quirine F. Manson | 2018 | Netherlands | 106 | 53 | Retrospective | clone sp263 (R) | 14 (13.2%) | H-scores>0 | OS | R (M/U) | 61.2 (15.6–310.8) | 6 |
| Sang Byung Bae | 2016 | Korea | 465 | 52.3 (24–81) | Retrospective | E1L3N (R) | 63 (13.5%) | H-score ≥100 | OS/DFS | R (M) | 41 (1–158) | 8 |
| In Hae Park | 2015 | Korea | 333 | 47 (28–78) | Retrospective | Abcam (R) | 163 (48.9%) | H-score≥2+-3+ | OS/DFS | R (U) | 117.6 (4.8–153.6) | 8 |
| Rhiannon K Beckers | 2015 | Australia | 161 | 57 (28–89) | Retrospective | E1L3N (R) | 123 (76.4) | H-score≥100 | OS/CSS | R (U) | 55 (0–213) | 7 |
| S. Muenst | 2014 | Switzerland | 650 | 64 (27–101) | Retrospective | Abcam (R) | 152 (23.4%) | H-score ≥100 | OS | R (M/U) | 65 (1–174) | 6 |
| Zhenhua Li | 2016 | China | 501 | 53 (29–83) | Retrospective | ab58810 (R) | 231 (46.1%) | H-score ≥100 | OS/RFS | R (M/U) | 64 (1–80) | 8 |
USA = United States of America, N = number of patients, NA = not applicable, R/M = rabbit/mouse, OS = overall survival, DFS = disease free survival, RFS = recurrence free survival, TNBC = triple negative breast cancer, R(M) = the HR come from multivariate analysis, R(U) = the HR comes from univariate analysis, NOS score = The Newcastle-Ottawa Scale (NOS) score.