Does diabetes affect [18F]FDG standardised uptake values in lung cancer?

The correlation of hyperglycaemia with decreased 2-[18F]fluoro-2-deoxy-D-glucose (FDG) uptake by tumours in positron emission tomography (PET) imaging has been clearly established. The available data are mainly based on non-diabetic (non-DM) patients exposed to acute hyperglycaemia after glucose infusion, and little is known about the effect of diabetes mellitus (DM) on FDG uptake by tumours. In this retrospective study we performed a comparison of the tumour uptake in 40 DM patients with the tumour uptake in 145 non-DM patients, all with primary lung malignancies. Peak standardised uptake values (SUVs) without glucose correction were calculated for the lung lesions. Mean (±standard deviation) blood glucose concentrations were 6.58±2.46 mmol/l in the DM patients and 4.39±0.89 mmol/l in the non-DM patients. There was no significant difference between tumour SUVs in DM patients (79 lesions), 5.86±3.97, and those in non-DM patients (234 lesions), 6.47±4.61. There was no significant difference between tumour SUVs in DM patients with blood glucose 7 mmol/l (n=12, 15 lesions), 5.68±4.09. There was also no significant difference between myocardial SUVs in the DM patients (n=40), 3.28±2.75, and in a similar group of non-DM patients (n=42), 3.30±2.24. We conclude that FDG uptake in lung tumours is not significantly influenced by blood glucose levels in diabetic patients whose blood glucose levels are reasonably well controlled.