Meta-Analysis
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 14, 2019; 25(30): 4278-4291
Published online Aug 14, 2019. doi: 10.3748/wjg.v25.i30.4278
Quantitative risk of positive family history in developing colorectal cancer: A meta-analysis
Parsa Mehraban Far, Abdulaziz Alshahrani, Mohammad Yaghoobi
Parsa Mehraban Far, Division of Medicine, Queen’s University, Kingston, ON K7L 3N6, Canada
Abdulaziz Alshahrani, Mohammad Yaghoobi, Division of Gastroenterology, McMaster University, Hamilton, ON L8S 4K1, Canada
Mohammad Yaghoobi, The Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, ON L8S 4K1, Canada
Author contributions: Yaghoobi M designed the study, completed the statistical analyses and prepared the manuscript. Mehraban Far P and Alshahrani A performed the study and prepared the manuscript.
Conflict-of-interest statement: Yaghoobi M’s research is partly supported by an Internal Career Award by the Department of Medicine, McMaster University.
Data sharing statement: No additional data is available.
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 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 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/
Corresponding author: Mohammad Yaghoobi, FACG, FRCP (C), MD, MSc, DABIM, AFS, Assistant Professor, Division of Gastroenterology, McMaster University, 1280 Main St West, Hamilton, ON L8S 4K1, Canada. yaghoob@mcmaster.ca
Telephone: +1-905-5259140
Received: March 20, 2019
Peer-review started: March 20, 2019
First decision: April 11, 2019
Revised: July 6, 2019
Accepted: July 19, 2019
Article in press: July 19, 2019
Published online: August 14, 2019
Abstract
BACKGROUND

Positive family history is a risk factor for development of colorectal cancer. Despite numerous studies on the topic, the absolute risk in patients with a positive family history remains unclear and therefore studies are lacking to validate non-invasive screening methods in individuals with positive family history.

AIM

To quantify the risk of colorectal cancer in individuals with a positive family history.

METHODS

A comprehensive electronic literature search was performed using PubMed from January 1955 until November 2017, EMBASE from 1947 until 2018, and Cochrane Library without date restrictions. Two independent reviewers conducted study selection, data extraction and quality assessment. A meta-analysis of Mantel-Haenzel relative risks was performed using the random effects model. Newcastle-Ottawa scale was used to score the quality of selected papers. Funnel plot and Egger’s regression test was performed to detect publication bias. Subgroup analysis was performed comparing Asian and non-Asian studies. Sensitivity analyses were performed to rule out the effect of the timing of the study, overall quality, the main outcome and the effect of each individual study in overall result.

RESULTS

Forty-six out of 3390 studies, including 906981 patients were included in the final analysis. 41 of the included studies were case-control and 5 were cohort. A positive family history of colorectal cancer in first-degree relatives was associated with significantly increased risk of colorectal cancer with a relative risk of 1.87 (95%CI: 1.68-2.09; P < 0.00001). Cochrane Q test was significant (P < 0.00001, I2 = 90%). Egger’s regression test showed asymmetry in the funnel plot and therefore the Trim and Fill method was used which confirmed the validity of the results. There was no difference between Asian versus non-Asian studies. Results remained robust in sensitivity analyses.

CONCLUSION

Individuals with a positive family history of colorectal cancer are 1.87 times more likely to develop colorectal cancer. Screening guidelines should pay specific attention to individuals with positive family history and further studies need to be done on validating current screening methods or developing new modalities in this high-risk population.

Keywords: Colorectal cancer, Risk, Family history

Core tip: The increased risk of developing colorectal cancer in individuals with a positive family history remains unknown. Many independent studies have provided different numerical risks with relatively large differences between the values. Here, we have performed a systematic review and meta-analysis to provide a more accurate estimate of this increased risk in an attempt to aid future guideline making and help implement preventative measures for at-risk individuals.