Published online May 21, 2018. doi: 10.3748/wjg.v24.i19.2120
Peer-review started: March 7, 2018
First decision: March 21, 2018
Revised: April 3, 2018
Accepted: April 16, 2018
Article in press: April 15, 2018
Published online: May 21, 2018
To clarify the previous discrepant conclusions, we performed a meta-analysis to evaluate the prognostic value of red cell distribution width (RDW) in esophageal cancer (EC).
We searched the PubMed, EMBASE, Web of Science and Cochrane Library databases to identify clinical studies, followed by using STATA version 12.0 for statistical analysis. Studies that met the following criteria were considered eligible: (1) Studies including EC patients who underwent radical esophagectomy; (2) studies including patients with localized disease without distant metastasis; (3) studies including patients without preoperative neoadjuvant therapy; (4) studies including patients without previous antiinﬂammatory therapies and with available preoperative laboratory outcomes; (5) studies reporting association between the preoperative RDW and overall survival (OS)/disease-free survival (DFS)/cancer-specific survival (CSS); and (6) studies published in English.
A total of six articles, published between 2015 and 2017, fulfilled the selection criteria in the end. Statistical analysis showed that RDW was not associated with the prognosis of EC patients, irrespective of OS/CSS [hazard ratio (HR) = 1.27, 95% confidence interval (CI): 0.97-1.57, P = 0.000] or DFS (HR = 1.42, 95%CI: 0.96-1.88, P = 0.000). Subgroup analysis indicated that elevated RDW was significantly associated with worse OS/CSS of EC patients when RDW > 13% (HR = 1.45, 95%CI: 1.13-1.76, P = 0.000), when the patient number ≤ 400 (HR = 1.45, 95%CI: 1.13-1.76, P = 0.000) and when the study type was retrospective (HR = 1.42, 95%CI : 1.16-1.69, P = 0.000).
Contrary to our general understanding, this meta-analysis revealed that RDW cannot serve as an indicator of poor prognosis in patients with EC. However, it may still be a useful predictor of unfavorable prognosis using an appropriate cut-off value.
Core tip: Red cell distribution width (RDW) has been established as a prognostic factor for cancer patients. In consideration of esophageal cancer (EC), many articles have concluded that RDW is correlated with poor prognosis. However, recent studies have indicated that elevated RDW harbors no prognostic value for EC, which might, instead, be a favorable prognostic factor for EC patients. No consensus is available in the previous literature concerning whether elevated RDW is a negative or favorable prognostic factor for EC patients. To this end, for the first time, this systematic review and meta-analysis was performed to evaluate the prognostic value of RDW in EC.