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Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Jun 15, 2016; 8(6): 481-488
Published online Jun 15, 2016. doi: 10.4251/wjgo.v8.i6.481
Colorectal cancer in the young, many questions, few answers
Kemal I Deen, Hiroshi Silva, Raeed Deen, Pramodh C Chandrasinghe
Kemal I Deen, Consultant in Colon and Rectal Surgery, The Asiri Surgical Hospital, Colombo 11600, Sri Lanka
Hiroshi Silva, Pramodh C Chandrasinghe, The University of Kelaniya Medical School, Ragama 11600, Sri Lanka
Raeed Deen, The University of Sydney Medical School, Sydney NSW 2006, Australia
Author contributions: All authors equally contributed to this paper with conception and design, literature review and analysis, drafting and critical revision and editing, and final approval of the final version.
Conflict-of-interest statement: No potential conflicts of interest relevant to this article were reported.
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: Kemal I Deen, MD, MS, FRCS, FACRSI, FNat, Ac Sci, Consultant in Colon and Rectal Surgery, The Asiri Surgical Hospital, No.21 Kirimandala Mawatha, Colombo 11600, Sri Lanka.
Telephone: +94-777-746158
Received: January 4, 2016
Peer-review started: January 5, 2016
First decision: January 30, 2016
Revised: February 29, 2016
Accepted: March 14, 2016
Article in press: March 16, 2016
Published online: June 15, 2016

At a time where the incidence of colorectal cancer, a disease predominantly of developed nations, is showing a decline in those 50 years of age and older, data from the West is showing a rising incidence of this cancer in young individuals. Central to this has been the 75% increase in rectal cancer incidence in the last four decades. Furthermore, predictive data based on mathematical modelling indicates a 124 percent rise in the incidence of rectal cancer by the year 2030 - a statistic that calls for collective global thought and action. While predominance of colorectal cancer (CRC) is likely to be in that part of the large bowel distal to the splenic flexure, which makes flexible sigmoidoscopic examination an ideal screening tool, the cost and benefit of mass screening in young people remain unknown. In countries where the incidence of young CRC is as high as 35% to 50%, the available data do not seem to indicate that the disease in young people is one of high red meat consuming nations only. Improvement in our understanding of genetic pathways in the aetiology of CRC, chiefly of the MSI, CIN and CIMP pathway, supports the notion that up to 30% of CRC is genetic, and may reflect a familial trait or environmentally induced changes. However, a number of other germline and somatic mutations, some of which remain unidentified, may play a role in the genesis of this cancer and stand in the way of a clear understanding of CRC in the young. Clinically, a proportion of young persons with CRC die early after curative surgery, presumably from aggressive tumour biology, compared with the majority in whom survival after operation will remain unchanged for five years or greater. The challenge in the future will be to determine, by genetic fingerprinting or otherwise, those at risk of developing CRC and the determinants of survival in those who develop CRC. Ultimately, prevention and early detection, just like for those over 50 years with CRC, will determine the outcome of CRC in young persons. At present, aside from those with an established familial tendency, there is no consensus on screening young persons who may be at risk. However, increasing awareness of this cancer in the young and the established benefit of prevention in older persons, must be a message that should be communicated with medical students, primary health care personnel and first contact doctors. The latter constitutes a formidable challenge.

Keywords: Colon cancer, Young age, Rectal cancer, Colorectal cancer, Young patients, Survival, Early onset

Core tip: This review of colorectal cancer in the young focuses on new data that reveal CRC to be more a left sided cancer than previously thought and the predicted rise by the year 2030. The article outlines the genetics of colorectal cancer (CRC) and discusses limitation in current knowledge in establishing a fingerprint for sporadic CRC. Aside from diet in its aetiology, luminal alkalinity and the colonic microbiome may be contributory and require further research. The review discusses the need for increased awareness of CRC in the young and the need for global consensus on screening young people at risk.