Meta-Analysis
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Dec 15, 2020; 12(12): 1443-1455
Published online Dec 15, 2020. doi: 10.4251/wjgo.v12.i12.1443
Prognostic impact of at least 12 lymph nodes after neoadjuvant therapy in rectal cancer: A meta-analysis
Ling Tan, Zi-Lin Liu, Zhou Ma, Zhou He, Lin-Han Tang, Yi-Lei Liu, Jiang-Wei Xiao
Ling Tan, Zi-Lin Liu, Zhou Ma, Zhou He, Lin-Han Tang, Yi-Lei Liu, Jiang-Wei Xiao, Department of Gastrointestinal Surgery, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, Chengdu 610500, Sichuan Province, China
Author contributions: Tan L and Liu ZL performed data acquisition, analysis, and interpretation, and drafted the manuscript; Ma Z, He Z, Tang LH, and Liu YL contributed to data interpretation and revised the manuscript; Xiao JW contributed to study conception and design, and critical revision of the manuscript; all authors approved the final version of the submitted manuscript.
Supported by the National Natural Science Foundation of China, No. 81070378 and 81270561; and Special Research Fund for The First Affiliated Hospital of Chengdu Medical College, No. CYFY2019YB08.
Conflict-of-interest statement: All the authors declare that they have no conflict of interest to disclose.
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 that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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/
Corresponding author: Jiang-Wei Xiao, MD, PhD, Postdoc, Professor, Surgeon, Surgical Oncologist, Teacher, Department of Gastrointestinal Surgery, Clinical Medical College and The First Affiliated Hospital of Chengdu Medical College, No. 278 Zhongduan Baoguang Avenue, Xindu District, Chengdu 610500, Sichuan Province, China. xiaojiangwei2018@163.com
Received: August 5, 2020
Peer-review started: August 5, 2020
First decision: September 24, 2020
Revised: September 28, 2020
Accepted: October 20, 2020
Article in press: October 20, 2020
Published online: December 15, 2020
Processing time: 127 Days and 4.2 Hours
Abstract
BACKGROUND

The number of dissected lymph nodes (LNs) in rectal cancer after neoadjuvant therapy has a controversial effect on the prognosis.

AIM

To investigate the prognostic impact of the number of LN dissected in rectal cancer patients after neoadjuvant therapy.

METHODS

We performed a systematic review and searched PubMed, Embase (Ovid), MEDLINE (Ovid), Web of Science, and Cochrane Library from January 1, 2000 until January 1, 2020. Two reviewers examined all the publications independently and extracted the relevant data. Articles were eligible for inclusion if they compared the number of LNs in rectal cancer specimens resected after neoadjuvant treatment (LNs ≥ 12 vs LNs < 12). The primary endpoints were the overall survival (OS) and disease-free survival (DFS).

RESULTS

Nine articles were included in the meta-analyses. Statistical analysis revealed a statistically significant difference in OS [hazard ratio (HR) = 0.76, 95% confidence interval (CI): 0.66-0.88, I2 = 12.2%, P = 0.336], DFS (HR = 0.76, 95%CI: 0.63-0.92, I2 = 68.4%, P = 0.013), and distant recurrence (DR) (HR = 0.63, 95%CI: 0.48-0.93, I2 = 30.5%, P = 0.237) between the LNs ≥ 12 and LNs < 12 groups, but local recurrence (HR = 0.67, 95%CI: 0.38-1.16, I2 = 0%, P = 0.348) showed no statistical difference. Moreover, subgroup analysis of LN negative patients revealed a statistically significant difference in DFS (HR = 0.67, 95%CI: 0.52-0.88, I2 = 0%, P = 0.565) between the LNs ≥ 12 and LNs < 12 groups.

CONCLUSION

Although neoadjuvant therapy reduces LN production in rectal cancer, our data indicate that dissecting at least 12 LNs after neoadjuvant therapy may improve the patients’ OS, DFS, and DR.

Keywords: Rectal cancer; Neoadjuvant therapy; Lymph node; Prognostic; Overall survival; Meta-analysis

Core Tip: After neoadjuvant treatment of rectal cancer, the lymph node (LN) output is significantly reduced. There is no consensus on the relationship between the number of LNs resected and the prognosis of rectal cancer after neoadjuvant treatment. This is the first meta-analysis to compare the impact of the number of LNs on the prognosis of rectal cancer after neoadjuvant treatment. We studied the effects of resection of at least 12 LNs and less than 12 LNs after neoadjuvant treatment of rectal cancer on overall survival, disease-free survival, distant recurrence, and local recurrence.