Elevated fasting glucose is common in lung cancer patients undergoing 18F-FDG PET/CT: A brief report

To characterize glycemic profiles among patients with lung cancer undergoing standardized capillary fasting blood glucose (cFBG) assessment prior to fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging.

Consecutive lung cancer patients scheduled for FDG PET/CT were enrolled at the University Hospital Zurich. cFBG was measured before FDG PET/CT and classified according to American Diabetes Association guidelines. Additional analyses were performed in subgroups examined before 11 a.m. and in patients without known diabetes. Multivariable linear regression was used to identify independent factors associated with cFBG levels.

The cohort included 240 lung cancer patients (median age 67 years, IQR 60-73; 41 % female, 99/240; median BMI 24 kg/m², IQR 21-27), of whom 13 % (30/240) had a prior diabetes diagnosis. The median cFBG was 104 mg/dL (IQR 95-115; 5.8 mmol/L, IQR 5.3-6.4). Non-normal cFBG (≥100 mg/dL, ≥5.6 mmol/L) was found in 63 % (151/240) of patients which was consistent in the subgroup presenting before 11 a.m. (58 %, 72/124). Excluding patients with known diabetes, 60 % (125/210) of patients had non-normal cFBG levels, with 8 % (16/210) having levels ≥126 mg/dL (≥7.0 mmol/L), indicative of undiagnosed diabetes mellitus. Multivariable linear regression analysis showed that traditional risk factors such as body mass index were not independently associated with cFBG levels, and neither subcutaneous nor visceral fat were significant predictors.

More than half of lung cancer patients presenting for PET/CT had non-normal fasting glucose levels, even in the absence of traditional risk factors or known diabetes, underscoring the need for improved screening and management strategies in this population.