Meta-Analysis
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 21, 2018; 24(19): 2120-2129
Published online May 21, 2018. doi: 10.3748/wjg.v24.i19.2120
Prognostic impact of the red cell distribution width in esophageal cancer patients: A systematic review and meta-analysis
Wei-Yu Xu, Xiao-Bo Yang, Wen-Qin Wang, Yi Bai, Jun-Yu Long, Jian-Zhen Lin, Jian-Ping Xiong, Yong-Chang Zheng, Xiao-Dong He, Hai-Tao Zhao, Xin-Ting Sang
Wei-Yu Xu, Xiao-Bo Yang, Yi Bai, Jun-Yu Long, Jian-Zhen Lin, Jian-Ping Xiong, Yong-Chang Zheng, Hai-Tao Zhao, Xin-Ting Sang, Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
Wen-Qin Wang, Xiao-Dong He, Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
Author contributions: Xu WY and Yang XB contributed equally to this work; Xu WY conceived, designed and wrote the manuscript that led to the submission; Xu WY, Yang XB and Wang WQ searched and filtered the literature; Long JY, Lin JZ and Xiong JP selected and interpreted the data; Wang WQ and Zheng YC revised the manuscript; Zhao HT and Sang XT provided financial support for this work; He XD, Zhao HT and Sang XT are co-corresponding authors, and they contributed equally to this work; All authors read and approved the final manuscript.
Supported by CAMS Innovation Fund for Medical Science (CIFMS), No. 2017-12M-4-003; International Science and Technology Cooperation Projects, No. 2015DFA30650 and No. 2016YFE0107100; Capital Special Research Project for Health Development, No. 2014-2-4012; and Beijing Natural Science Foundation, No. L172055.
Conflict-of-interest statement: The authors deny any conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Xin-Ting Sang, MD, Professor, Department of Liver Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, 1 Shuaifuyuan, Wangfujing, Beijing 100730, China. sangxt@pumch.cn
Telephone: +86-10-69156042 Fax: +86-10-69156042
Received: March 7, 2018
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
Processing time: 71 Days and 18.5 Hours
Abstract
AIM

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).

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Keywords: Red cell distribution width; Prognostic impact; Systematic review; Meta-analysis

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.