Systematic Reviews
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 28, 2016; 22(4): 1721-1726
Published online Jan 28, 2016. doi: 10.3748/wjg.v22.i4.1721
Systematic review of prognostic importance of extramural venous invasion in rectal cancer
Manish Chand, Muhammed RS Siddiqui, Ian Swift, Gina Brown
Manish Chand, Muhammed RS Siddiqui, Gina Brown, Royal Marsden Hospital, London SM2 5PT, United Kingdom
Ian Swift, Croydon University Hospital, London CR7 9YE, United Kingdom
Author contributions: Chand M, Siddiqui MRS, Swift I and Brown G all contributed equally to the manuscript in design and writing the manuscript; Chand M and Siddiqui MRS performed the review of literature; Siddiqui MRS analysed the data.
Conflict-of-interest statement: None to declare.
Data sharing statement: This study does not contain patient data; and no additional data 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:
Correspondence to: Manish Chand, Research Fellow, Colorectal Surgeon, Department of Radiology, Royal Marsden Hospital, London SM2 5PT, United Kingdom.
Telephone: +44-208-9106067 Fax: +44-208-9106067
Received: April 5, 2015
Peer-review started: April 20, 2015
First decision: June 23, 2015
Revised: July 14, 2015
Accepted: November 9, 2015
Article in press: November 9, 2015
Published online: January 28, 2016

AIM: To systematically review the survival outcomes relating to extramural venous invasion in rectal cancer.

METHODS: A systematic review was conducted using PRISMA guidelines. An electronic search was carried out using MEDLINE, EMBASE, CINAHL, Cochrane library databases, Google scholar and PubMed until October 2014. Search terms were used in combination to yield articles on extramural venous invasion in rectal cancer. Outcome measures included prevalence and 5-year survival rates. These were graphically displayed using Forest plots. Statistical analysis of the data was carried out.

RESULTS: Fourteen studies reported the prevalence of extramural venous invasion (EMVI) positive patients. Prevalence ranged from 9%-61%. The pooled prevalence of EMVI positivity was 26% [Random effects: Event rate 0.26 (0.18, 0.36)]. Most studies showed that EMVI related to worse oncological outcomes. The pooled overall survival was 39.5% [Random effects: Event rate 0.395 (0.29, 0.51)].

CONCLUSION: Historically, there has been huge variation in the prevalence of EMVI through inconsistent reporting. However the presence of EMVI clearly leads to worse survival outcomes. As detection rates become more consistent, EMVI may be considered as part of risk-stratification in rectal cancer. Standardised histopathological definitions and the use of magnetic resonance imaging to identify EMVI will improve detection rates in the future.

Keywords: Extramural venous invasion, Rectal cancer, Overall survival, Pathology, Vascular invasion, Magnetic resonance imaging

Core tip: Extramural venous invasion (EMVI) has been shown to be an adverse risk factor in rectal cancer. Historical studies have shown a wide range of prevalence which has made survival risk difficult to interpret. This has been due to lack of standardised detection methods. As these methods improve, we are more likely to be able to identify those patients with evidence of EMVI and thus offer patients optimal treatment.