Meta-Analysis
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Surg. Oct 27, 2023; 15(10): 2331-2342
Published online Oct 27, 2023. doi: 10.4240/wjgs.v15.i10.2331
Bariatric surgery reduces colorectal cancer incidence in obese individuals: Systematic review and meta-analysis
Ying-Ning Liu, Jing-Feng Gu, Jian Zhang, Dong-Yang Xing, Gui-Qi Wang
Ying-Ning Liu, Jing-Feng Gu, Jian Zhang, Dong-Yang Xing, Gui-Qi Wang, Department of Gastrointestinal Surgery, The First Hospital of Hebei Medical University, Shijiazhuang 050011, Hebei Province, China
Author contributions: Liu YN and Gu JF contributed to the conception of the study; Zhang J and Liu YN contributed significantly to literature search, data extraction, quality assessment, data analyses and manuscript preparation; Xing DY contributed improving the article for language and style and protocol preparation; Gu JF helped perform the analysis with constructive discussions; Wang GQ revised the manuscript and approved the final version.
Conflict-of-interest statement: The authors Ying-Ning Liu, Jing-Feng Gu, Jian Zhang, Dong-Yang Xing and Gui-Qi Wang all declare that there are no conflicts of interest related to this study.
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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Gui-Qi Wang, MM, Chief Doctor, Department of Gastrointestinal Surgery, The First Hospital of Hebei Medical University, No. 89 Donggang Road, Shijiazhuang 050011, Hebei Province, China. doc_wangguiqi@163.com
Received: July 9, 2023
Peer-review started: July 9, 2023
First decision: August 10, 2023
Revised: August 14, 2023
Accepted: August 21, 2023
Article in press: August 21, 2023
Published online: October 27, 2023
ARTICLE HIGHLIGHTS
Research background

Obesity, with varying global definitions due to body fat disparities between Western and Asian populations, elevates colorectal cancer risk by 7% to 60%. Weight loss surgeries, especially Roux-en-Y laparoscopic gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG), reduce this risk. Our meta-analysis addresses the varying post-surgery outcomes and research gaps from prior studies.

Research motivation

LRYGB and LSG surgeries exhibit potential impacts on colorectal cancer, but current studies show inconsistencies. Our research aims to bridge these gaps, informing clinical choices, shaping policies, and directing future investigations.

Research objectives

To quantitatively analyze the link between obesity and colorectal cancer, assess the impact of LRYGB and LSG surgeries, discern gender-specific risks, and refine methodological approaches in meta-analyses.

Research methods

We conducted a comprehensive search on PubMed, Embase, Web of Science, and Cochrane Library using terms including "obesity," "colorectal cancer," "gastric bypass," and "sleeve gastrectomy." We then assessed the retrieved articles based on the PRISMA-guided the Population, Intervention, Comparison, Outcome, and Study design framework: Population (adults with morbid obesity), Intervention (weight loss surgery), Comparison (observation or other treatments), Outcome (risk of colorectal cancer), and Study design (comparative studies with minimum ten patients/group).

Research results

Analyzing 17 studies with over 12 million patients, we found that bariatric surgery (BS) patients had a 54% reduced colorectal cancer risk. Subgroup insights showed a 46% risk reduction in females post-BS, while male trends were inconclusive. Specific surgical methods like sleeve gastrectomy and RYGB didn't show differential benefits. Rigorous hazard ratio and Newcastle-Ottawa Scale assessments validated our findings, with no detected publication bias. However, distinct outcomes for colon and rectal cancer remained unresolved.

Research conclusions

Bariatric surgery notably lowers colorectal cancer risk, especially in females, irrespective of the surgical type. Our expansive meta-analysis, adhering to rigorous standards, offers a nuanced insight into this relationship.

Research perspectives

Future studies should unravel the mechanisms behind bariatric surgery's protective effect, explore gut microbiota's role, compare surgery types, assess long-term impacts, and consider confounding factors.