Table 1 Baseline characteristics of studies included in the meta-analysis
Study | Publication year | Country | Study design | Sample size | Mean age (years) | Disease stages | Treatment strategy | Cutoff value | Adjusted or not | Reported outcomes | NOS scale |
|---|---|---|---|---|---|---|---|---|---|---|---|
Hernandez et al. [33] | 1992 | USA | Retrospective | 113 | 59.2 | I–IV | Radiation | 400 | Not | OS | 5 |
Lopes et al. [37] | 1994 | England | Retrospective | 643 | 45.5 | Ib–IV | Surgery or radiation | 400 | Not | OS | 7 |
Hernandez et al. [32] | 1994 | USA | Retrospective | 623 | NS | Ib | Surgery | 400 | Not | OS, PFS | 7 |
Rodriguez et al. [40] | 1994 | USA | Retrospective | 219 | 40.0 | Ib | Surgery | 300 | Not | OS | 5 |
De Jonge et al. [28] | 1999 | South Africa | Retrospective | 93 | NS | Ib | Surgery | 400 | Yes | OS, RFS | 6 |
Hernandez et al. [31] | 2000 | USA | Retrospective | 291 | 49.8 | IIb–IVa | Surgery or radiation | 400 | Yes | OS | 6 |
Qiu et al. [39] | 2010 | China | Retrospective | 318 | 43.0 | I–IV | NS | 400 | Not | OS | 6 |
Gadducci et al. [29] | 2010 | Italy | Retrospective | 46 | 47.0 | Ib–IIb | Surgery or chemotherapy | 272 | Not | OS, RFS | 6 |
Gadducci et al. [30] | 2010 | Italy | Retrospective | 140 | 47.0 | Ib–IIb | Surgery or chemotherapy | 272 | Not | OS, RFS | 6 |
Wang et al. [41] | 2012 | China | Retrospective | 111 | 42.0 | Ib–IIb | Surgery or chemotherapy | 266 | Not | OS, PFS | 5 |
Biedka et al. [27] | 2012 | Poland | Retrospective | 58 | NS | I–IV | Surgery or radiation | NS | Not | PFS | 5 |
Zhao et al. [44] | 2015 | China | Retrospective | 220 | NS | I–IIa | Surgery | 300 | Not | OS, RFS | 6 |
Xiao et al. [42] | 2015 | China | Retrospective | 238 | 52.0 | I–IV | Radiation and chemotherapy | 200 | Not | OS, PFS | 6 |
Li et al. [36] | 2015 | China | Retrospective | 380 | 51.0 | Ia–IIb | Surgery | 300 | Not | OS | 6 |
Koulis et al. [34] | 2017 | Canada | Retrospective | 257 | 50.0 | Ib–IV | Chemoradiotherapy and surgery | 400 | Yes (OS), No (PFS) | OS, PFS | 7 |
Kozasa et al. [35] | 2017 | Japan | Retrospective | 684 | NS | I–IV | Chemoradiotherapy and surgery | 350 | Yes | OS, PFS | 7 |
Zheng et al. [45] | 2017 | China | Retrospective | 800 | 49.5 | Ia–IIa | Surgery | 272 | Yes | OS, RFS | 7 |
Nakamura et al. [38] | 2018 | Japan | Retrospective | 98 | 65.0 | I–IV | Radiation and chemotherapy | 350 | Not | OS, PFS | 6 |
Xu et al. [43] | 2018 | China | Retrospective | 1189 | NS | Ia–IIa | Surgery | 300 | Yes | PFS | 7 |