Table 1.
Characteristics of included studies
| Author | Year | Country | Sample (M/F) | Treatment | Survival analysis | Pathological type | HR (95% CI) | Cut-off level (mg/L) | TNM stage I–II/III–IV |
|---|---|---|---|---|---|---|---|---|---|
| Nozoe et al26 | 2001 | Japan | 262 (227/35) | C/R + S | OS | SCC + AC | 3.300 (2.174–5.000) | 5 | 157/105 |
| Ikeda et al27 | 2003 | Japan | 356 (327/29) | C/R + S + C/R | OS | SCC + AC + OT | 1.52 (1.05–2.21) | 5 | 186/170 |
| Shimada et al28 | 2003 | Japan | 150 (128/22) | S | OS | SCC | 1.42 (0.83–2.41) | 10 | 67/83 |
| Gockel et al29 | 2006 | Germany | 291 (NA) | S | OS | SCC + AC + OT | 1.182 (1.030–1.356) | 5 | NA |
| Wang et al30 | 2009 | Taiwan | 123 (120/3) | R | OS | SCC + AC | 12.116 (3.449–42.567) | 5 | 22/101 |
| Zingg et al31 | 2010 | Australia | 90 (74/16) | C/R + S | OS | SCC + AC | 1.42 (0.71–2.85) | 10 | 75/15 |
| Feng et al32 | 2013 | People’s Republic of China | 43 (30/13) | S + C/R | OS | SCCE | 2.756 (1.115–6.813) | 10 | NA |
| Song et al33 | 2013 | People’s Republic of China | 156 (134/22) | S + C/R | OS | SCC | 2.131 (1.213–4.451) | 5 | NA |
Abbreviations: M/F, male/female; S, surgery; C/R, chemotherapy/radiotherapy; R, radiotherapy; OS, overall survival; SCC, squamous cell carcinoma; AC, adenocarcinoma; OT, others; SCCE, small cell carcinoma of the esophagus; NA, not available; HR, hazard ratio; CI, confidence interval; TNM, tumor-node-metastasis.