Table 2.
Summary of calculated meta-relative risks (mRRs) for the seven prognostic factors of interest, including mRRs stratified by study size and annual patient volumea
| Prognostic factor | Number of studies | Overall mRR (95% CI) | P-valueb | Number of studies | mRR (95% CI) by study size | P-value | Number of studiesc | mRR (95% CI) by patient volume per study center | P-value |
|---|---|---|---|---|---|---|---|---|---|
| CEA level (≥200) | 9 | 1.92 (1.14–3.22) | <0.0001 | <200: 4 | <200: 2.49 (0.96–6.49) | <200: 0.034 | <20: 4 | <20: 2.19 (1.64–2.9) | <20: 0.616 |
| ≥200: 5 | ≥200: 1.68 (0.90–3.14) | ≥200: <0.0001 | ≥20: 4 | ≥20: 1.23 (0.51–2.96) | ≥20: 0.001 | ||||
| Extrahepatic disease (yes vs no) | 13 | 1.88 (1.50–2.37) | <0.0001 | <200: 3 | <200: 2.43 (1.22–4.83) | <200: <0.0001 | <20: 5 | <20: 2.35 (1.66–3.34) | <20: 0.001 |
| ≥200: 10 | ≥200: 1.74 (1.41–2.15) | ≥200: 0.001 | ≥20: 8 | ≥20: 1.55 (1.28–1.88) | ≥20: 0.032 | ||||
| Tumor grade (poor differentiation) | 7 | 1.88 (1.32–2.67) | <0.0001 | <200: 3 | <200: 2.88 (2.15–3.84) | <200: 0.808 | <20: 4 | <20: 2.51 (1.91–3.29) | <20: 0.356 |
| ≥200: 4 | ≥200: 1.43 (1.15–1.78) | ≥200: 0.195 | ≥20: 2 | ≥20: 1.65 (1.19–2.29) | ≥20: 0.713 | ||||
| Positive resection margin (yes vs no) | 20 | 2.02 (1.65–2.48) | <0.0001 | <200: 9 | <200: 2.52 (1.73–3.66) | <200: 0.044 | <20: 10 | <20: 2.53 (1.77–3.61) | <20: 0.044 |
| ≥200: 11 | ≥200: 1.82 (1.44–2.30) | ≥200: <0.0001 | ≥20: 10 | ≥20: 1.79 (1.41–2.27) | ≥20: <0.0001 | ||||
| 1+ liver metastasesd | 36 | 1.57 (1.39–1.78) | <0.0001 | <200: 17 | <200: 1.74 (1.29–2.34) | <200: <0.0001 | <20: 16 | <20: 1.46 (1.20–1.79) | <20: <0.0001 |
| ≥200: 19 | ≥200: 1.52 (1.34–1.71) | ≥200: <0.0001 | ≥20: 19 | ≥20: 1.66 (1.40–1.96) | ≥20: <0.0001 | ||||
| Node positive (yes vs no) | 20 | 1.59 (1.46–1.73) | 0.548 | <200: 13 | <200: 1.84 (1.55–2.19) | <200: 0.626 | <20: 13 | <20: 1.64 (1.47–1.84) | <20: 0.632 |
| ≥200: 7 | ≥200: 1.52 (1.38–1.67) | ≥200: 0.645 | ≥20: 7 | ≥20: 1.55 (1.33–1.79) | ≥20: 0.309 | ||||
| .3 cm tumor diameter | 20 | 1.52 (1.28–1.80) | <0.0001 | <200: 11 | <200: 1.57 (1.24–1.98) | <200: <0.0001 | <20: 5 | <20: 2.00 (1.51–2.64) | <20: 0.058 |
| ≥200: 9 | ≥200: 1.43 (1.24–1.64) | ≥200: 0.754 | ≥20: 13 | ≥20: 1.32 (1.15–1.51) | ≥20: <0.0001 |
Notes:
The estimated annual clinic volume was calculated as: initial patient population/number of years over which patients were recruited/number of centers participating in the study. Stratifications by study size and annual clinic volume were based on the median number of patients per center (n = 236) and median annual clinic volume (n = 21) of all studies included in the meta-analysis, thus the stratifications were performed using values of 200 (≥ and <) and 20 (≥ and <), respectively;
P-value is for heterogeneity of meta-analysis for all columns;
number of studies included in the analysis by patient volume not equal to total number of studies; data were not reported in some studies to calculate a patient volume;
includes variety of categories: “multiple” and various iterations of more than one metastasis.
Abbreviations: CEA, carcinoembryonic antigen; CI, confidence interval.