Retrospective Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 28, 2022; 28(48): 6950-6961
Published online Dec 28, 2022. doi: 10.3748/wjg.v28.i48.6950
Clinical features and long-term outcomes of patients with colonic oligopolyposis of unknown etiology
Dan Feldman, Linda Rodgers-Fouche, Stephanie Hicks, Daniel C Chung
Dan Feldman, Division of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
Linda Rodgers-Fouche, Stephanie Hicks, Center for Cancer Risk Assessment, Massachusetts General Hospital, Boston, Massachusetts 02114, United States
Daniel C Chung, Division of Gastroenterology and Center for Cancer Risk Assessment, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, United States
Author contributions: Feldman D contributed to conceptualization and design, formal analysis and interpretation, investigation, resources and acquisition of data, methodology, visualization, writing, revising, and editing the draft critically for important intellectual content; Rodgers-Fouche L contributed to conceptualization, resources and acquisition of data, writing, revising, and editing the draft critically for important intellectual content; Hicks S contributed to conceptualization, resources and acquisition of data, writing, revising, and editing the draft critically for important intellectual content; Chung DC contributed to conceptualization and design, formal analysis and interpretation, investigation, methodology, resources and acquisition of data, supervision, visualization, writing - original draft, writing, revising, and editing the draft critically for important intellectual content; All authors have read and approve the final manuscript.
Institutional review board statement: IRB approval (No. 2016P000516) was obtained by the Massachusetts General Hospital (MGH), For Retrospective Review and analysis of data, specimens, and/or records using the Hereditary GI Cancer Database.
Informed consent statement: Because of the retrospective and anonymous character of this study, the need for informed consent was waived by the institutional review board.
Conflict-of-interest statement: All authors declare no conflicts-of-interest related to this article.
Data sharing statement: Data are not available due to patient privacy restrictions and the absence of consent for public sharing.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article 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 NonCommercial (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: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Daniel C Chung, MD. Medical Co-Director, Center for Cancer Risk Assessment. Director, High-Risk GI Cancer Clinic, GI Division, Massachusetts General Hospital, Blossom Street, Boston, MA 02114. United States. chung.daniel@mgh.harvard.edu
Received: October 2, 2022
Peer-review started: October 2, 2022
First decision: November 3, 2022
Revised: November 14, 2022
Accepted: December 13, 2022
Article in press: December 13, 2022
Published online: December 28, 2022
Processing time: 85 Days and 22.5 Hours
Abstract
BACKGROUND

Colonic adenomatous polyposis of unknown etiology (CPUE) is an adenomatous polyposis phenotype that resembles Familial Adenomatous Polyposis (FAP) even though no germline pathogenic variant is identified.

AIM

We sought to better characterize the clinical features and outcomes in a cohort of CPUE patients.

METHODS

This is a retrospective case series of patients 18 years old or older with aden-omatous oligopolyposis (between 10-100 adenomas) and negative genetic testing, identified through the Hereditary Gastrointestinal Cancer Database at Massachusetts General Hospital, a tertiary academic referral center. A retrospective chart review was performed with a focus on demographics, alcohol and tobacco use, medication use, familial malignancy and polyp burden, genetic testing information, endoscopic surveillance data including the corresponding histopathology, colonic and extracolonic malignancies, mortality events, and their etiology. Spearman correlation and Pearson Chi-square test (or Fisher's exact test) were used for continuous and categorical variables respectively.

RESULTS

CPUE patients were primarily male (69%) and presented for genetic counseling at 63.7 years. Only 2 patients (2.9%) reported a first-degree relative with polyposis. During an average surveillance period of 12.3 years, 0.5 colonoscopies per year were performed. Patients developed 2.3 new adenomas per year. 4 (5.7%) were diagnosed with colorectal cancer (CRC) at a mean age of 66 years, and 3 were diagnosed prior to the onset of oligopolyposis. 7 (10%) required colectomy due to advanced dysplasia or polyp burden. With respect to upper gastrointestinal manifestations, 1 patient had a gastric adenoma, but there were no cases of gastric or small bowel polyposis. During surveillance, 10 (14%) patients died at a mean age of 72, and none were due to CRC.

CONCLUSION

CPUE is distinct from familial adenomatous polyposis (FAP) syndrome and the use of FAP surveillance guidelines may result in unnecessarily frequent upper and lower endoscopies.

Keywords: Colonic polyposis of unknown etiology; Multigene cancer panel; Colorectal cancer; Colectomy; Surveillance; Mortality

Core Tip: Colonic adenomatous polyposis of unknown etiology (CPUE) resembles familial adenomatous polyposis (FAP) syndrome, but no genetic alterations are identified. The optimal management of CPUE is uncertain. Patients with CPUE are typically older males that exhibit a low rate of new adenoma formation without upper gastrointestinal polyposis during long-term surveillance. 10% required colectomy for polyposis, and none died from colon cancer. The clinical behavior of CPUE is distinct from FAP, and the current application of FAP surveillance guidelines for CPUE may result in unnecessarily frequent upper and lower endoscopies.