Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Jan 14, 2015; 21(2): 423-431
Published online Jan 14, 2015. doi: 10.3748/wjg.v21.i2.423
Magnetic resonance imaging based rectal cancer classification: Landmarks and technical standardization
Sami Alasari, Daero Lim, Nam Kyu Kim
Sami Alasari, Daero Lim, Nam Kyu Kim, Department of General Surgery, Section of Colorectal Surgery at Yonsei University, Severance Hospital, Seoul 120-527, South Korea
Author contributions: Alasari S contributed to design, data acquisition, conception, analysis and interpretation of data, writing the manuscript, maintaining the database, obtaining follow-up data, providing criticism, drafting and revising the manuscript critically for important intellectual content; Lim D contributed to design, data acquisition; Kim NK contributed to design, final approval of the version to be published and revising the article critically.
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: Nam Kyu Kim, MD, Professor, Chairman, Department of General Surgery, Section of Colorectal Surgery at Yonsei University, Severance Hospital, 250 seongsan-ro, seodaemun-gu, Seoul 120-527, South Korea.
Telephone: +82-2-22282117 Fax: +82-2-3138289
Received: August 14, 2014
Peer-review started: August 14, 2014
First decision: September 27, 2014
Revised: October 12, 2014
Accepted: November 11, 2014
Article in press: November 11, 2014
Published online: January 14, 2015

Rectal cancer classification is important to determine the preoperative chemoradiation therapy and to select appropriate surgical technique. We reviewed the Western and Japanese rectal cancer classification and we propose our new classification based of Magnetic resonance imaging (MRI). We determine the relation of the tumor to fixed parameters in MRI, which are peritoneal reflection and levator ani muscle. Then, we classify the rectal cancer into four levels based on tumor distal margin and invasion to MRI parameters. We applied all three classifications to 60 retrospectively collected patients of different rectal cancer distance and we compared our classifications to the others. Based on each level we standardize our surgical approach. For stages I-III, We found that level I where tumor distal margin is located above the peritoneal reflection and all of them were received low anterior resection (LAR) without chemoradiation. Level II where tumor distal margin is located from the peritoneal reflection and above the levator ani insertion on the rectum. 90% of them were received LAR ± chemoradiation. Level III where tumor distal margin is located at the level of levator ani insertion or invading any part of the levator ani. 60% of them had ULAR + coloanal anastomosis ± chemoradiation. Level IV where the tumor distal margin is located below the levator ani insertion; 77% were received APR ± chemoradiation. The overall kappa for all levels between surgeons and radiologist was 0.93 (95%CI: 0.87-0.99), which is indicating almost perfect agreement. We concluded that the management of rectal tumors differed among each tumor level and our new MRI based classification might facilitate the prediction of surgical and chemoradiation management with better communication among a multidisciplinary team comparing to other classifications.

Keywords: Rectal cancer, Rectal classification, Surgical approach

Core tip: We reviewed the current rectal cancer classification and we propose a new rectal cancer classification based on new radiological parameters that might lead to change in the future decision making and management. We provide a comparison between our new novel classification, Western and Japanese one.