TABLE 2.
The basic characteristics of the included studies.
| Author | Year | Country | Study type | Sample size (N) | GPS = 0 | GPS = 1 | GPS = 2 | Age (years) | Gender (M/F) | Follow-up (months) | Stage | Treatment | Lung cancer type |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Forrest (7) | 2003 | United Kingdom | PO and RO | 161 | 27 | 101 | 33 | <60 (37); >60 (124) | 105/56 | NA | III–IV | Non-surgery (RT + CT) | Squamous (64); Adenocarcinoma (53); Others (44) |
| Forrest (14) | 2004 | United Kingdom | PO | 109 | 27 | 69 | 13 | <60 (41); >60 (68) | 63/46 | NA | III–IV | Non-surgery (CT) | Squamous (40); Adenocarcinoma (46); Others (23) |
| Forrest (33) | 2005 | United Kingdom | PO | 101 | 32 | 59 | 10 | <60 (18); >60 (83) | 62/39 | NA | III–IV | Non-surgery (NA) | NA |
| Miyazaki (29) | 2015 | Japan | RO | 97 | 65 | 25 | 7 | >80 | 62/35 | NA | I–IV | Surgery | NA |
| Fan (28) | 2016 | China | RO | 1745 | 668 | 647 | 430 | ≤55 (160); >55, ≤70 (754); >70 (831) | 1,217/528 | 20 (median) | I–IV | Non-surgery (CT) | NA |
| Yotsukura (24) | 2016 | Japan | RO | 1,048 | 817 | 184 | 47 | <65 (481); ≥65 (567) | 597/451 | NA | I–II | Surgery | Squamous (180); Adenocarcinoma (754); Others (114) |
| Miyazaki (23) | 2017 | Japan | RO | 108 | 99 | 4 | 5 | 82 (80–93) | 69/39 | NA | I–IV | Surgery | Adenocarcinoma (76); Others (32) |
| Tomita (21) | 2018 | Japan | RO | 341 | 191 | 112 | 38 | <65 (106); ≥65 (235) | 173/168 | NA | I–III | Surgery | Adenocarcinoma (268); Others (73) |
| Kasahara (20) | 2019 | Japan | RO | 47 | 24 | 6 | 17 | < 65 (14); ≥65 (33) | 37/10 | NA | I–IV | Non-surgery (IO) | Squamous (12); Others (35) |
| Kasahara (18) | 2020 | Japan | RO | 214 | 141 | 43 | 30 | <65 (62); ≥65 (152) | 83/131 | NA | I–IV | Non-surgery (EGFR-TKI) | Adenocarcinoma (212); Others (2) |
| Takamori (15) | 2021 | Japan | RO | 304 | 109 | 85 | 110 | <65 (104); ≥65 (208) | 242/62 | NA | IIIb–IV | Non-surgery (IO) | Squamous (74); Others (230) |
| Tomita (32) | 2014 | Japan | RO | 312 | 264 | 31 | 17 | <65 (104); ≥65 (208) | 192/129 | NA | I–III | Surgery | Adenocarcinoma (237); Others (75) |
| Lindenmann (17) | 2020 | Australia | PO | 300 | 229 | 68 | 3 | 65.4 ± 10.0 (20–87) | 187/113 | 38.1 ± 28.3 | I | Surgery | Squamous (95); Adenocarcinoma (191); Others (14) |
| Machida (27) | 2016 | Japan | RO | 156 | 136 | 16 | 4 | <65 (70); ≥65 (86) | 75/81 | 48.0 | IA–IIIA | Surgery | Adenocarcinoma |
| Kawashima (30) | 2015 | Japan | RO | 1,043 | 897 | 107 | 39 | NA | 671/372 | 36.0–60.0 | I–III | Surgery | Squamous (220); Adenocarcinoma (741); Others (82) |
| Jiang (31) | 2014 | China | PO | 138 | 95 | 32 | 11 | 55 (37–81) | 117/21 | 24.0–60.0 | IIIB–IV | Non-surgery (CT) | Squamous (67); Adenocarcinoma (48); Others (23) |
| Osugi (26) | 2016 | Japan | RO | 327 | 286 | 30 | 11 | ≤69 (171); >69 (156) | 199/128 | ≥60.0 | I–III | Surgery | Squamous (78); Adenocarcinoma (232); Others (17) |
| Su (25) | 2016 | China | PO | 207 | 49 | 111 | 47 | <60 (126); ≥60 (81) | 144/63 | NA | IIIA–IV | Non-surgery (CT) | Squamous (63); Adenocarcinoma (127); Others (17) |
| Ni (22) | 2018 | China | RO | 436 | NO | NO | NO | ≤62 (228); >62 (208) | 297/139 | NA | III–IV | Non-surgery (RT + CT) | Squamous (107); Others (329) |
| Topkan (19) | 2019 | Japan | RO | 83 | 42 | 22 | 19 | >70 | 49/34 | NA | IIIb | Non-surgery (RT + CT) | Squamous (47); Adenocarcinoma (36) |
| Kikuchi (16) | 2020 | Japan | RO | 56 | 31 | 16 | 9 | 71 (65–77) | 40/16 | NA | III–IV | NA | Squamous (25); Adenocarcinoma (28); Others (3) |
GPS, Glasgow Prognostic Score; N, numbers of studies; p, p-values of Q test; NA, not available; PO, prospective studies; RO, retrospective studies; CT, chemo therapy; RT, radiation therapy; IO, immunotherapy; EGFR-TKI, Epidermal growth factor receptor-tyrosine kinase inhibitor.