Table 2 Meta-analysis results of overall survival and hazard rates in further analysis
| Â | Â | Â | Â | Heterogeneity | ||
|---|---|---|---|---|---|---|
Pooled value | Studies | OR | HR | 95% CI | P value | I2 |
Compare positive para-aortic lymph node group with negative group | ||||||
 3-year OS | 5 | 0.30 |  | 0.11–0.82 | 0.002 | 76% |
 5-year OS | 4 | 0.19 |  | 0.11–0.31 | 0.31 | 16% |
Compare complete resection group with not complete resection group | ||||||
 3-year OS | 5 | 5.26 |  | 2.02–13.69 | 0.14 | 42% |
OS | ||||||
 Histological differentiation (poor vs medium-high) | ||||||
  HR | 4 |  | 2.98 | 1.48–5.99 | 0.08 | 56% |
 Postoperative chemotherapy (yes vs no) | ||||||
  HR | 4 |  | 1.01 | 0.54–1.84 | 0.23 | 30% |
 Age (old vs young) | ||||||
  HR | 4 |  | 1.00 | 0.98–1.02 | 0.51 | 0 |
 The number of PALN metastases(≥4 vs <4) | ||||||
  HR | 3 |  | 1.88 | 0.97–3.62 | 0.20 | 39% |
 Primary tumor location (colon vs rectum) | ||||||
  HR | 3 |  | 0.93 | 0.54–1.59 | 0.42 | 0 |
 CEA (ng/ml)(<10 vs ≥10) | ||||||
  HR | 3 |  | 0.88 | 0.41–1.86 | 0.03 | 72% |
 T grade (T4+3 vs T1-2) | ||||||
  HR | 3 |  | 1.35 | 0.74–2.46 | 0.46 | 0 |
Disease-free survival | ||||||
 Preoperative extra-retroperitoneal metastases (yes vs no) | ||||||
  HR | 4 |  | 1.85 | 1.10–3.10 | 0.75 | 0 |
 Primary tumor location (colon vs rectum) | ||||||
  HR | 3 |  | 1.29 | 0.74–2.25 | 0.41 | 0 |