Table 2. Summary of the meta-analysis results.
| Analysis | Ctegories | n | Model | HR (95% CI) | Z | P | Heterogeneity | |
|---|---|---|---|---|---|---|---|---|
| I2 | Ph | |||||||
| Overall survival (OS) | 12 (3661) | Random | 1.375 (1.200–1.576) | 4.58 | < 0.001 | 58.1% | 0.006 | |
| Study region: | Eastern countries | 11 (3426) | Fixed | 1.203 (1.141–1.256) | 8.31 | < 0.001 | 25.9% | 0.197 |
| Western countries | 1 (235) | random | 3.322 (1.905–5.792) | 4.23 | < 0.001 | NA | NA | |
| Clinical stage: | Stage I–II | 6 (1924) | Fixed | 1.388 (1.140–1.691) | 3.26 | 0.001 | 23.0% | 0.261 |
| Stage I–IV | 5 (1677) | Random | 1.323 (1.112–1.573) | 3.16 | 0.002 | 73.8% | 0.004 | |
| Stage II–III | 1 (60) | Random | 1.829 (1.091–3.065) | 2.29 | 0.022 | NA | NA | |
| Sample size: | ≥ 100 | 7 (3299) | Random | 1.377 (1.185–1.601) | 4.17 | < 0.001 | 69.5% | 0.003 |
| < 100 | 5 (362) | Fixed | 1.347 (1.013–1.793) | 2.05 | 0.041 | 33.6% | 0.198 | |
| Cut-off value: | ≥ 2.5 | 6 (1522) | Random | 1.568 (1.161–2.118) | 2.93 | 0.003 | 68.4% | 0.007 |
| < 2.5 | 6 (2139) | Random | 1.369 (1.071–1.749) | 2.51 | 0.012 | 49.8% | 0.077 | |
| Primary treatment: | Surgery + NACT | 2 (186) | Fixed | 1.127 (0.834–1.523) | 0.78 | 0.436 | 47.6% | 0.167 |
| Surgery + AT | 4 (1738) | Fixed | 1.623 (1.251–2.106) | 3.64 | < 0.001 | 0.0% | 0.606 | |
| CCRT | 3 (390) | Random | 2.092 (1.361–4.382) | 3.00 | 0.003 | 52.2% | 0.124 | |
| Radiotherapy or CCRT | 2 (286) | Fixed | 1.186 (1.074–1.309) | 3.38 | 0.001 | 48.7% | 0.163 | |
| Mixed | 1 (1061) | Random | 1.190 (1.130–1.250) | 6.76 | < 0.001 | NA | NA | |
| Analysis method: | Multivariate | 8 (2600) | Random | 1.354 (1.145–1.600) | 3.55 | < 0.001 | 68.6% | 0.002 |
| Univariate | 4 (1061) | Fixed | 1.470 (1.172–1.843) | 3.33 | 0.001 | 0.0% | 0.793 | |
| Progression free survival (PFS) | 10 (2452) | Random | 1.646 (1.313–2.065) | 4.31 | < 0.001 | 80.3% | < 0.001 | |
| Study region: | Eastern countries | 9 (2217) | Random | 1.496 (1.227–1.823) | 3.98 | < 0.001 | 71.9% | < 0.001 |
| Western countries | 1 (235) | Random | 3.579 (2.106–6.082) | 4.71 | < 0.001 | NA | NA | |
| Clinical stage: | Stage I–II | 4 (715) | Fixed | 1.740 (1.375–2.202) | 4.61 | < 0.001 | 38.0% | 0.184 |
| Stage I–IV | 5 (1677) | Random | 1.460 (1.097–1.943) | 2.60 | 0.009 | 83.3% | < 0.001 | |
| Stage II–III | 1 (60) | Random | 2.135 (1.274–3.579) | 2.88 | 0.004 | NA | NA | |
| Sample size | ≥ 100 | 5 (2097) | Random | 1.469 (1.096–1.970) | 2.57 | 0.010 | 81.8% | < 0.001 |
| < 100 | 5 (355) | Fixed | 1.752 (1.452–2.113) | 5.85 | < 0.001 | 17.1% | 0.306 | |
| Cut-off value | ≥ 2.5 | 6 (795) | Random | 1.606 (1.193–2.161) | 3.12 | 0.002 | 71.8% | 0.003 |
| < 2.5 | 4 (1657) | Random | 1.804 (1.100–2.958) | 2.34 | 0.019 | 83.9% | < 0.001 | |
| Primary treatment: | Surgery | 4 (715) | Fixed | 1.740 (1.375–2.202) | 4.61 | < 0.001 | 38.0% | 0.184 |
| CCRT | 3 (390) | Fixed | 2.457 (1.762–3.428) | 5.30 | < 0.001 | 45.6% | 0.159 | |
| Radiotherapy or CCRT | 2 (286) | Random | 1.282 (1.074–1.531) | 2.75 | 0.006 | 73.3% | 0.053 | |
| Mixed | 1 (1061) | Random | 1.130 (1.081–1.180) | 5.41 | < 0.001 | NA | NA | |
| Analysis method: | Multivariate | 6 (2118) | Random | 1.650 (1.226–2.220) | 3.30 | 0.001 | 86.1% | < 0.001 |
| Univariate | 4 (334) | Fixed | 1.635 (1.283–2.083) | 3.98 | < 0.001 | 0.0% | 0.537 | |
NACT neoadjuvant chemotherapy; AT adjuvant therapy; CCRT concurrent chemoradiotherapy.
P denotes P value for statistical significance based on Z test; Ph denotes P value for heterogeneity based on Q test. HR hazard ratio; CI confidence interval; NA not available.