Table 3.
Subgroup analyses of cancer types
| Subgroup | Number of studies | Summary RR (95% CIs) | I2 value | ph |
|---|---|---|---|---|
| Sex | ||||
| Overall | 12 | 0.97 (0.88, 1.07) | 47.0% | 0.036 |
| Colorectal cancer | 4 | 0.92 (0.80, 1.06) | 0.0% | 0.978 |
| Gastric cancer | 3 | 1.12 (0.97, 1.29) | 0.0% | 0.981 |
| HNSCC | 2 | 1.13 (0.95, 1.34) | 24.2% | 0.251 |
| EBDC | 1 | 0.79 (0.59, 1.07) | NA | NA |
| Lung cancer | 1 | 0.61 (0.44, 0.83) | NA | NA |
| ESCC | 1 | 0.96 (0.82, 1.11) | NA | NA |
| Tumor size | ||||
| Overall | 5 | 1.23 (0.94, 1.62) | 51.1% | 0.085 |
| Colorectal cancer | 2 | 0.99 (0.68, 1.44) | 46.7% | 0.171 |
| Breast cancer | 1 | 1.38 (0.98, 1.93) | NA | NA |
| Lung cancer | 1 | 1.42 (0.42, 4.85) | NA | NA |
| Gastric cancer | 1 | 1.60 (1.13, 2.27) | NA | NA |
| Differentiation | ||||
| Overall | 17 | 0.94 (0.72, 1.21) | 75.1% | 0.000 |
| Colorectal cancer | 8 | 1.06 (0.74, 1.52) | 69.6% | 0.002 |
| Gastric cancer | 3 | 0.63 (0.53, 0.75) | 0.0% | 0.978 |
| Breast cancer | 2 | 1.07 (0.72, 1.60) | 0.0% | 0.548 |
| Prostate cancer | 1 | 0.87 (0.53, 1.41) | NA | NA |
| EBDC | 1 | 2.70 (0.84, 8.63) | NA | NA |
| ESCC | 1 | 1.46 (0.81, 2.64) | NA | NA |
| HNSCC | 1 | 0.39 (0.15, 1.01) | NA | NA |
| Lymphatic invasion | ||||
| Overall | 10 | 1.36 (1.15, 1.61) | 62.3% | 0.005 |
| Colorectal cancer | 4 | 1.36 (1.09, 1.68) | 56.7% | 0.074 |
| Gastric cancer | 2 | 1.23 (0.55, 2.73) | 85.4% | 0.009 |
| EBDC | 1 | 1.31 (0.97, 1.78) | NA | NA |
| Lung cancer | 1 | 2.53 (0.39, 16.31) | NA | NA |
| Gallbladder cancer | 1 | 1.39 (0.92, 2.11) | NA | NA |
| ESCC | 1 | 1.71 (1.40, 2.08) | NA | NA |
| Venous invasion | ||||
| Overall | 13 | 1.41 (1.18, 1.67) | 52.9% | 0.013 |
| Colorectal cancer | 5 | 1.57 (1.33, 1.84) | 0.0% | 0.746 |
| Gastric cancer | 3 | 1.48 (1.04, 2.12) | 35.6% | 0.212 |
| Breast cancer | 1 | 0.69 (0.42, 1.11) | NA | NA |
| EBDC | 1 | 0.95 (0.61, 1.49) | NA | NA |
| Lung cancer | 1 | 3.16 (0.50, 19.87) | NA | NA |
| Gallbladder cancer | 1 | 1.05 (0.68, 1.64) | NA | NA |
| ESCC | 1 | 2.05 (1.48, 2.83) | NA | NA |
| T stage | ||||
| Overall | 18 | 1.14 (1.04, 1.27) | 59.6% | 0.001 |
| Colorectal cancer | 7 | 1.22 (1.08, 1.38) | 65.6% | 0.008 |
| Gastric cancer | 4 | 1.04 (0.85, 1.28) | 29.7% | 0.234 |
| Breast cancer | 2 | 0.66 (0.31, 1.40) | 0.0% | 0.895 |
| EBDC | 1 | 1.13 (0.79, 1.62) | NA | NA |
| Lung cancer | 1 | 0.83 (0.66, 1.04) | NA | NA |
| Gallbladder cancer | 1 | 1.00 (0.47, 2.14) | NA | NA |
| ESCC | 1 | 2.09 (1.43, 3.06) | NA | NA |
| HNSCC | 1 | 0.91 (0.71, 1.17) | NA | NA |
| N stage | ||||
| Overall | 23 | 1.46 (1.29, 1.66) | 55.1% | 0.001 |
| Colorectal cancer | 9 | 1.54 (1.34, 1.75) | 24.5% | 0.226 |
| Gastric cancer | 4 | 1.28 (1.11, 1.47) | 0.0% | 0.393 |
| Breast cancer | 3 | 1.46 (1.04, 2.04) | 41.6% | 0.180 |
| Lung cancer | 3 | 2.00 (0.44, 8.97) | 80.2% | 0.006 |
| EBDC | 1 | 1.06 (0.57, 1.97) | NA | NA |
| Gallbladder cancer | 1 | 1.13 (0.56, 2.29) | NA | NA |
| ESCC | 1 | 2.70 (1.98, 3.68) | NA | NA |
| HNSCC | 1 | 1.23 (0.83, 1.83) | NA | NA |
| M stage | ||||
| Overall | 14 | 1.76 (1.34, 2.31) | 42.1% | 0.049 |
| Colorectal cancer | 5 | 1.47 (1.15, 1.87) | 9.2% | 0.354 |
| Gastric cancer | 2 | 3.23 (1.67, 6.22) | 0.0% | 0.678 |
| Lung cancer | 2 | 3.21 (1.07, 9.69) | 0.0% | 0.871 |
| Breast cancer | 1 | 1.35 (0.20, 9.16) | NA | NA |
| EBDC | 1 | 1.19 (0.60, 2.37) | NA | NA |
| ESCC | 1 | 5.25 (2.18, 12.67) | NA | NA |
| HNSCC | 1 | 0.89 (0.39, 2.05) | NA | NA |
| OSCC | 1 | 1.24 (0.70, 2.21) | NA | NA |
| Tumor stage | ||||
| Overall | 15 | 1.42 (1.19, 1.68) | 69.9% | 0.000 |
| Colorectal cancer | 8 | 1.58 (1.36, 1.82) | 13.0% | 0.328 |
| Gastric cancer | 2 | 1.11 (0.88, 1.39) | 19.5% | 0.265 |
| HNSCC | 1 | 1.08 (0.79, 1.49) | 58.7% | 0.120 |
| Breast cancer | 1 | 0.90 (0.27, 2.97) | NA | NA |
| EBDC | 1 | 1.12 (0.74, 1.70) | NA | NA |
| ESCC | 1 | 3.04 (1.95, 4.73) | NA | NA |
Note: ph: P-value for heterogeneity within each subgroup.
Abbreviations: RR, relative risk; CI, confidence interval; HNSCC, head and neck squamous cell carcinoma; OSCC, oral squamous cell carcinoma; EBDC, extrahepatic bile duct carcinoma; ESCC, esophageal squamous cell carcinoma; NA, not available.