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
Processing time: 147 Days and 12.3 Hours
ARTICLE HIGHLIGHTS
Research background

Colorectal cancer is one of the most common and dangerous malignancies which is likely caused by a combination of environmental and genetic factors. Although it has been long known that individuals with a positive family history of colorectal cancer are at an increased risk of developing this cancer, a robust quantitative estimate of this increased risk is not available in the medical literature with large variability between individual studies.

Research motivation

Estimating the increased risk of individuals with a positive family history of colorectal cancer could be crucial for the development of preventative and screening guidelines for these individuals. The currently existing screening guidelines for individuals with a positive family history are not based on high quality evidence or absent all-together.

Research objectives

The objective of this report was to accurately estimate the risk of developing colorectal cancer in patients with a positive family history.

Research methods

This project was a meta-analysis of case-control and cohort studies of colorectal cancer patients. Data from individual papers was extracted to independently calculate a relative risk of colorectal cancer in patients with a positive family history.

Research results

We found that a positive family history of colorectal cancer in first-degree relatives is associated with significantly increased risk of colorectal cancer with a relative risk of 1.87 (95%CI: 1.68-2.09; P < 0.00001). Future research should aim to determine the influence of environmental factors such as diet and exercise on the familial risk of developing colorectal cancer.

Research conclusions

We found that individuals with a positive family history of colorectal cancer have almost 2-fold higher chance of developing this cancer. To our knowledge, this is the first manuscript in the past decade which estimated the risk of familial colorectal cancer. Our results can substantially contribute to the development of new screening guidelines for individuals with a positive family history.

Research perspective

More research is required to gain a better understanding of the influence of environmental factors on the familial risk of colorectal cancer. In addition, future projects should determine whether the number of first degree relatives affected and their age of initial diagnosis has an effect on the increased risk of this cancer.