Retrospective Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 14, 2018; 24(2): 257-265
Published online Jan 14, 2018. doi: 10.3748/wjg.v24.i2.257
Timing of surgery after neoadjuvant chemotherapy for gastric cancer: Impact on outcomes
Yi Liu, Ke-Cheng Zhang, Xiao-Hui Huang, Hong-Qing Xi, Yun-He Gao, Wen-Quan Liang, Xin-Xin Wang, Lin Chen
Yi Liu, Ke-Cheng Zhang, Xiao-Hui Huang, Hong-Qing Xi, Yun-He Gao, Wen-Quan Liang, Xin-Xin Wang, Lin Chen, Department of General Surgery & Institute of General Surgery, Chinese People’s Liberation Army General Hospital, Beijing 100853, China
Author contributions: Liu Y and Zhang KC designed the study and wrote the manuscript; Xi HQ and Huang XH contributed to the patient material; Liu Y collected the clinical data; Gao YH and Liang WQ contributed to data analysis and validation; all authors have reviewed and approved the final manuscript.
Supported by the Beijing Municipal Science and Technology Plan, No. D141100000414002; and the National Natural Science Foundation of China, No. 81272698, No. 81672319, and No. 81602507.
Institutional review board statement: The study was approved by the Chinese People’s Liberation Army General Hospital Research Ethics Committee.
Informed consent statement: Informed consent was not required because all the study participants had signed a consent form prior to neoadjuvant chemotherapy and the analysis used anonymous clinical data.
Conflict-of-interest statement: All the authors have no conflict of interest.
Data sharing statement: All data from which the conclusion could be drawn are presented in the manuscript. No additional data are available.
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: Lin Chen, MD, PhD, Professor, Chief, Department of General Surgery & Institute of General Surgery, Chinese People’s Liberation Army General Hospital, 28 Fuxing Road, Beijing 100853, China. chenlinbj301@163.com
Telephone: +86-10-66938128 Fax: +86-10-68181689
Received: November 20, 2017
Peer-review started: November 21, 2017
First decision: December 6, 2017
Revised: December 8, 2017
Accepted: December 13, 2017
Article in press: December 13, 2017
Published online: January 14, 2018
ARTICLE HIGHLIGHTS
Research background

The impact of the interval time from the completion of neoadjuvant chemotherapy (NACT) to surgery on pathological complete response (pCR) and survival has been proved in rectal cancer and esophageal cancer. However, the optimal NACT-surgery interval time and its association with survival, to the best of our knowledge, have never been investigated in gastric cancer. This study can provide evidence for the timing of surgery and patients with neoadjuvant chemotherapy may benefit from it.

Research motivation

To investigate whether the interval time between NACT and surgery have an impact on pCR was our main topic. The investigation lays a foundation for the further RCT research.

Research objectives

There were two objectives in this study. The primary objective was to evaluate the impact of NACT-surgery interval time on pCR rate and the optimal timing of operation. The secondary objective was to determine the association between NACT-surgery interval time and 3-year OS or disease-free survival (DFS). If the impacts are existent, more studies will focus on the investigation of optimal interval time and this evidence will bring a change in treatment plan for GC patients with neoadjuvant chemotherapy.

Research methods

This is a retrospective study, in which we realized our objectives through data analysis using bivariate analysis, logistic regression analysis, and Cox proportion hazards regression. These methods are routinely used in studies and have high stability.

Research results

The impact of the NACT-surgery interval time on pCR has been proved and the interval time > 6 wk can increase the chance of a pCR. Clinical T stage also have an impact on pCR. The independent predictors of long-term survival are ypN stage and surgical procedure. These findings for the first time proved the impact of the NACT-surgery interval time on pCR in gastric cancer and give a reference for the optimal interval time. The further investigations of accurate optimal interval time are needed.

Research conclusions

The authors for the first time investigated and found the impact of the NACT-surgery interval time on pCR, and the optimal interval time may be > 6 wk. This result is consistent with those from previous rectal and esophageal cancer studies, and we speculate that it may be the result of multiple factors, including the ongoing effect of radiochemotherapy, changes in the tumor microenvironment, and recovery of immunity from chemotherapy. Additional basic medical studies may be needed to explain it.

Research perspectives

Further studies, either retrospective or prospective, are needed to investigate more interval time groups with a large sample size. Also, it is meaningful to investigate the mechanism of this finding through basic medical studies.