Table 2. Subgroup analyses of the potential effects of CTCs on survival outcomes in esophageal cancer patients.
| Disease progression* | Overall survival | |||||||
|---|---|---|---|---|---|---|---|---|
| n | HR(95%CI) | pheterogeneity | I2(%) | n | HR(95%CI) | pheterogeneity | I2(%) | |
| Sampling time | ||||||||
| NR | 1 | 0.76(0.56-1.03) | - | - | 2 | 2.80(0.29-27.53) | 0.0029 | 79.2 |
| baseline | 7 | 2.65(1.95-3.60) | 0.334 | 12.5 | 7 | 3.39(2.22-5.20) | 0.285 | 19.0 |
| post-therapy | 5 | 2.15(1.54-3.01) | 0.475 | 0 | 2 | 1.69(0.94-3.01) | 0.631 | 0 |
| Sample size | ||||||||
| <50 | 3 | 2.83(1.53-5.24) | 0.864 | 0 | 5 | 2.68(0.87-8.27) | 0.398 | 1.5 |
| ≧50 | 10 | 2.21(1.41-3.47) | <0.001 | 79.9 | 6 | 2.65(1.59-4.43) | 0.009 | 67.3 |
| Detection method | ||||||||
| RT-PCR | 11 | 2.26(1.47-3.47) | <0.001 | 78.4 | 10 | 2.61(1.54-4.43) | 0.024 | 53.1 |
| IE/IF | 2 | 2.75(1.28-5.88) | 0.601 | 0 | ||||
| CellSearch | 1 | 2.81(1.96-4.02) | - | - | ||||
| Detection rate(%) | ||||||||
| <30 | 2 | 1.79(1.28-2.51) | 0.619 | 0 | 5 | 2.80(1.72-4.54) | 0.127 | 44.3 |
| ≧30 | 11 | 2.52(1.51-4.20) | <0.001 | 79.1 | 5 | 1.83(0.66-5.07) | 0.052 | 57.3 |
| CTC markers | ||||||||
| CEA mRNA | 1 | 0.76(0.56-1.03) | - | - | 2 | 1.06(0.51-2.22) | 0.808 | 0 |
| CK19 mRNA | 2 | 2.14(1.30-3.51) | 0.706 | 0 | 3 | 3.06(0.65-14.37) | 0.150 | 47.4 |
| Survivin mRNA | 3 | 4.01(2.49-6.45) | 0.375 | 0 | 2 | 5.76(2.72-12.20) | 0.491 | 0 |
| SCCA mRNA | 1 | 3.00(1.05-8.56) | - | - | 1 | 3.53(0.07-172.16) | - | - |
| CEA & SCCA mRNA | 2 | 1.79(1.28-2.51) | 0.619 | 0 | 2 | 1.96(1.27-3.05) | 0.373 | 0 |
| CEA, CK19 & Survivin mRNA | 2 | 3.08(1.50-6.35) | 0.606 | 0 | - | - | - | - |
*
Disease progression outcomes include disease-free survival (DFS) and progression-free survival (PFS).
Abbreviations: RT-PCR, reverse transcription-polymerase chain reaction; IE/IF, Immunomagnetic enrichment/immunofluorescence staining; NR, not reported; CEA, carcinoembryonic antigen; CK19, cytokeratin 19; SCCA, squamous cell carcinoma antigen; CTC, circulating tumor cells; -, when the record number ≦1, the pheterogeneity and I2 cannot be calculated.