Retrospective Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jun 16, 2022; 10(17): 5634-5645
Published online Jun 16, 2022. doi: 10.12998/wjcc.v10.i17.5634
Assessment of incidental focal colorectal uptake by analysis of fluorine-18 fluorodeoxyglucose positron emission tomography parameters
Haejun Lee, Kyung-Hoon Hwang, Kwang An Kwon
Haejun Lee, Kyung-Hoon Hwang, Department of Nuclear Medicine, Gachon University College of Medicine, Gil Medical Center, Incheon 21565, South Korea
Kwang An Kwon, Department of Gastroenterology, Gachon University College of Medicine, Gil Medical Center, Incheon 21565, South Korea
Author contributions: Lee H and Hwang KH contributed to this work; Lee H and Hwang KH designed the research study; Lee H, Kwon KA and Hwang KH performed the research; Lee H contributed analytic tools; Lee H, Kwon KA and Hwang KH analyzed the data and wrote the manuscript; and all authors have read and approved the final manuscript.
Institutional review board statement: The study was reviewed and approved by the Institutional Review Board at our institution. The requirement for informed consent was waived.
Conflict-of-interest statement: The authors have no potential conflicts of interest to disclose.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at [forrest88@hanmail.net]. Informed consent for data sharing was waived because of the retrospective nature of the study and this retrospective study was approved by the Institutional Review Board of our hospital (IRB No. GAIRB2020-297).
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: Kyung-Hoon Hwang, MD, PhD, Professor, Department of Nuclear Medicine, Gachon University College of Medicine, Gil Medical Center, 21, Namdong-daero 774 beon-gil, Namdong-gu, Incheon 21565, South Korea. forrest88@hanmail.net
Received: December 27, 2021
Peer-review started: December 27, 2021
First decision: January 25, 2022
Revised: February 11, 2022
Accepted: April 9, 2022
Article in press: April 29, 2022
Published online: June 16, 2022
Processing time: 164 Days and 3.1 Hours
ARTICLE HIGHLIGHTS
Research background

Intestinal fluorine-18 fluorodeoxyglucose (F-18 FDG) uptake is often observed on positron emission tomography/computed tomography (PET/CT). However, unexpectedly observed focal colorectal hypermetabolism might harbor a risk of malignancy; thus, distinguishing malignant from benign tumors is critical.

Research motivation

As with other cancers, early lesion detection is critical in colorectal cancer. As surgery may still be the treatment of choice for cure in selected patients with advanced colorectal cancer, the importance of early detection of lesions is even greater.

Research objectives

To assess the implications of focal colorectal F-18 FDG uptake by analyzing FDG PET parameters.

Research methods

This study included 83 focal colorectal hypermetabolic regions from 80 patients. Each region was classified as malignant, premalignant, or benign according to the histopathological report. PET parameters such as maximum and peak standardized uptake values (SUVmax and SUVpeak), metabolic tumor volume (MTV), mean SUV of metabolic tumor volume (mSUVmtv), and total lesion glycolysis (TLG) of F-18 FDG PET/CT were measured and calculated for the regions, and compared among malignant, premalignant, malignant/premalignant, and benign hypermetabolic regions. Receiver operating characteristic (ROC) curves were plotted to determine the cut-off values for these parameters.

Research results

Of the 83 incidentally observed focal colorectal hypermetabolic regions on F-18 FDG PET-CT, 61.4% (51/83) were malignant/premalignant lesions confirmed by histopathological reports of the corresponding locations. SUVmax, SUVpeak, and mSUVmtv can be used to differentiate malignant and premalignant lesions from benign lesions. SUVmax, with an AUC of 0.770 and a cut-off of 7.6 (confidence interval: 0.668–0.872, sensitivity 0.686, specificity 0.688) was the superior FDG PET parameter in distinguishing malignant and premalignant from benign lesions.

Research conclusions

Approximately two-thirds (61.4%) of the incidental focal hypermetabolic colorectal regions were malignant/premalignant. SUVmax was demonstrated as an independent diagnostic parameter for the lesions. Unexpected suspicious focal colorectal FDG uptake should not be avoided and further evaluation is required.

Research perspectives

Controversies and debates regarding the parameters assessed in this study remain ongoing. Further studies with larger numbers of subjects are warranted.