Gastrointestinal 18F-FDG accumulation on PET without a corresponding CT abnormality is not an early indicator of cancer development

Abstract

Focal gastrointestinal 2-deoxy-2-[(18)F]-fluoro-D: -glucose (FDG) uptake can frequently be found on FDG-PET/CT even in patients without known gastrointestinal malignancy. The aim of this study was to evaluate whether increased gastrointestinal FDG uptake without CT correlate is an early indicator of patients developing gastrointestinal malignancies. A total of 1,006 patients without esophagogastric or anorectal malignancies underwent FDG-PET/CT. The esophagogastric junction, the stomach and the anorectum were evaluated for increased FDG uptake. Patients without elevated uptake were assigned to group A, patients with elevated uptake were allocated to group B. The SUVmax values of both groups were tested for significant differences using the U test. A follow-up of longer than 1 year (mean 853 +/- 414 days) served as gold standard. A total of 460 patients had to be excluded based on insufficient follow-up data. For the remaining 546 patients the mean SUVmax was as follows: (a) esophagogastric junction, group A 3.1 +/- 0.66, group B 4.0 +/- 1.11, p < 0.01; (b) stomach, group A 2.8 +/- 0.77, group B 4.1 +/- 1.33, p < 0.01; (c) rectal ampulla, group A 2.8 +/- 0.83, group B 3.9 +/- 1.49, p < 0.01; (d) anal canal, group A 2.7 +/- 0.55, group B 3.9 +/- 1.59, p < 0.01. Only one patient developed gastric cancer. In the case of an unremarkable CT, elevated esophagogastric or anorectal FDG uptake does not predict cancer development and does not have to be investigated further.

Japanese Gastric Cancer Association Task Force for Research Promotion: clinical utility of 18F-fluoro-2-deoxyglucose positron emission tomography in gastric cancer. A systematic review of the literature

“…Heusner et al [4] evaluated esophagogastric FDG uptake in 546 patients without esophagogastric malignancies. They concluded that elevated esophagogastric FDG uptake does not predict cancer development and should not be investigated further if CT shows no unusual features.…”

“…For gastric cancer screening, the usefulness of PET is limited because of physiological FDG uptake in the normal gastric wall and differences of FDG uptake according to the histological type of the tumor [1,2]. Physiological FDG deposits in the stomach may increase false-positive findings, although these deposits can be decreased by expanding the gastric wall by the patient consuming water or milk just before imaging acquisition [4,5]. As Koga et al [2] have reported, physiological gastric FDG uptake was shown to be significantly higher at the oral end; thus, strong gastric FDG uptake at the anal end suggested pathological uptake.…”

“…As Koga et al [2] have reported, physiological gastric FDG uptake was shown to be significantly higher at the oral end; thus, strong gastric FDG uptake at the anal end suggested pathological uptake. These authors [1,2,4,5] concluded that FDG accumulation in the stomach suggested a high probability of the presence of inflammatory change in the gastric mucosa froming a background for the development of cancer or malignant lymphoma; thus, FDG accumulation in the stomach requires further endoscopic examinations.…”

Influence of Bowel Preparation Before 18F-FDG PET/CT on Physiologic 18F-FDG Activity in the Intestine

“…In general, such tracer accumulation is only faint or moderate and diffuse. Such a pattern is usually easy to identify as nonpathologic, especially if morphologic abnormalities are absent (2). However, there are still a considerable number of patients with a higher and more focal accumulation of 18 F-FDG in the intestine.…”

Fluorine-18-fluorodeoxyglucose uptake in a benign oesophageal leiomyoma: a potential pitfall in diagnosis

“…In fact, the accumulation of 18 F-FDG in the distal oesophagus is not infrequent and Roedl et al [3] reported only 8.3% malignancy in incidental oesophageal 18 F-FDG uptake. Heusner et al [4] even postulated that an abnormal 18 F-FDG accumulation of the gastro-oesophageal junction does not need further investigation if there is no correlate on CT. Of course, in both of our presented cases, there was a mass on CT, justifying further investigation. In both cases, even after multiple biopsies were performed-although not advisable in leiomyomas-malignancy could not be confirmed.…”