Systematic Reviews
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Dec 15, 2016; 8(12): 826-834
Published online Dec 15, 2016. doi: 10.4251/wjgo.v8.i12.826
Colon adenoma features and their impact on risk of future advanced adenomas and colorectal cancer
Audrey H Calderwood, Karen E Lasser, Hemant K Roy
Audrey H Calderwood, Section of Gastroenterology, Department of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, United States
Karen E Lasser, Section of General Internal Medicine, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, United States
Hemant K Roy, Section of Gastroenterology, Department of Medicine, Boston University School of Medicine, Boston, MA 02118, United States
Author contributions: Calderwood AH designed the study, performed the literature search, drafted, edited and approved the final manuscript; Lasser KE designed the study; performed the literature search, drafted, edited and approved the final manuscript; Roy HK designed the study, performed the literature search, drafted, edited and approved the final manuscript.
Supported by (in part through) awarded grants from the National Institutes of Health, No. K08DK090150 to Calderwood AH, No. U01CA111257 to Roy HK, No. R01CA165309 to Roy HK, and No. R01CA156186 to Roy HK; and American Cancer Society Research Scholar Grant, No. RSG-14-034-01-CPPB to Lasser KE.
Conflict-of-interest statement: Roy HK has the following disclosures: Nanocytomics LLC, American BioOptics LLC, Pegasus BioSolutions LLC (not relevant for manuscript). The other authors have no potential conflicts of interest to report.
Data sharing statement: No additional data are 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: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Audrey H Calderwood, MD, MS, Section of Gastroenterology, Department of Medicine, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, NH 03756, United States. audrey.h.calderwood@hitchcock.org
Telephone: +1-603-6505261 Fax: +1-603-6505225
Received: April 1, 2016
Peer-review started: April 6, 2016
First decision: June 7, 2016
Revised: September 19, 2016
Accepted: November 1, 2016
Article in press: November 2, 2016
Published online: December 15, 2016
Processing time: 249 Days and 13.6 Hours
Abstract
AIM

To review the evidence on the association between specific colon adenoma features and the risk of future colonic neoplasia [adenomas and colorectal cancer (CRC)].

METHODS

We performed a literature search using the National Library of Medicine through PubMed from 1/1/2003 to 5/30/2015. Specific Medical Subject Headings terms (colon, colon polyps, adenomatous polyps, epidemiology, natural history, growth, cancer screening, colonoscopy, CRC) were used in conjunction with subject headings/key words (surveillance, adenoma surveillance, polypectomy surveillance, and serrated adenoma). We defined non-advanced adenomas as 1-2 adenomas each < 10 mm in size and advanced adenomas as any adenoma ≥ 10 mm size or with > 25% villous histology or high-grade dysplasia. A combined endpoint of advanced neoplasia included advanced adenomas and invasive CRC.

RESULTS

Our search strategy identified 592 candidate articles of which 8 met inclusion criteria and were relevant for assessment of histology (low grade vs high grade dysplasia, villous features) and adenoma size. Six of these studies met the accepted quality indicator threshold for overall adenoma detection rate > 25% among study patients. We found 254 articles of which 7 met inclusion criteria for the evaluation of multiple adenomas. Lastly, our search revealed 222 candidate articles of which 6 met inclusion criteria for evaluation of serrated polyps. Our review found that villous features, high grade dysplasia, larger adenoma size, and having ≥ 3 adenomas at baseline are associated with an increased risk of future colonic neoplasia in some but not all studies. Serrated polyps in the proximal colon are associated with an increased risk of future colonic neoplasia, comparable to having a baseline advanced adenoma.

CONCLUSION

Data on adenoma features and risk of future adenomas and CRC are compelling yet modest in absolute effect size. Future research should refine this risk stratification.

Keywords: Colon adenoma; Colorectal cancer screening; Surveillance; Colonoscopy

Core tip: The data on adenoma size, adenoma multiplicity and serrated polyps in terms of risk for future adenomas and colorectal cancer are compelling, however, the absolute effect size is relatively modest. Current guideline recommendations to perform colonoscopy surveillance at 3-5 years after baseline adenomas and serrated polyps appear appropriately tailored to the risk of future neoplasia.