High and typical 18F-FDG bowel uptake in patients treated with metformin

Abstract

This study emphasizes that metformin significantly increases (18)F-FDG uptake in colon and, to a lesser extent, in small intestine. It raises the question of stopping metformin treatment before an (18)F-FDG PET/CT scan is performed for intra-abdominal neoplasic lesion assessment.

18F-FDG PET/CT for the assessment of gastrointestinal GVHD: results of a pilot study

“…The latter may have lead to false positive results in two patients in whom it was shown retrospectively that they were receiving metformin, a drug known to induce a significant increase of FDG uptake along the wall and into the intestinal lumen. 13 These two false positive results would have probably been avoided today thanks to the systematic discontinuation of metformin 2-3 days before the completion of 18 F-FDG PET/CT. Indeed, two recent studies have shown that stopping metformin 2-3 days before the completion of 18 F-FDG PET/CT could decrease significantly the gastrointestinal uptake of FDG.…”

“…For two of these patients, it appeared later that false positivity was related to daily treatment with metformin (not revealed to the nuclear medicine specialists who interpreted the tests) as previously described. 13 Figure 3 shows the results of one of the two FP patients who were taking metformin. For another one FP patient, false positivity was likely related to the presence of severe peptic esophagitis, proven later by endoscopy.…”

Investigating Metformin for Cancer Prevention and Treatment: The End of the Beginning

“…Although a systemic effect with this dose is unlikely, the observation is consistent with relatively high intraluminal metformin concentrations following oral administration. Indeed, it is of interest that reports in the clinical literature on 18-fl uoro-deoxy-glucose positron emission tomography (FDG-PET) have documented increased intestinal glucose uptake in patients receiving metformin ( 109 ). Although this was discussed in terms of its signifi cance in diagnostic imaging, it is possible that that the metforminassociated increased FDG-PET signal may represent a pharmacodynamic marker of metformin activation of AMPK in the intestine, leading to increased glucose uptake.…”

Roles of facilitative glucose transporter GLUT1 in [18F]FDG positron emission tomography (PET) imaging of human diseases

“…It may therefore be useful to cease metformin treatment before performing any oncologic [ 18 F]FDG PET assessment of the intraabdominal region [355]. Indeed, the discontinuation of metformin treatment for two or three days is [365].…”

“…The effects of anti-diabetic drugs on glucose metabolism have been assessed using [ of the large intestine and, to a lesser extent, in the small intestine [355,356]. It may therefore be useful to cease metformin treatment before performing any oncologic [ 18 F]FDG PET assessment of the intraabdominal region [355].…”