Diabetes Decreases FDG Accumulation in Primary Lung Cancer

Area of Science:

• Oncology
• Nuclear Medicine
• Metabolic Research

Background:

• Positron Emission Tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) is a key imaging modality for lung cancer.
• Diabetes mellitus affects glucose metabolism, potentially influencing FDG uptake in tumors.

Purpose of the Study:

• To compare the kinetics and accumulation of FDG in primary lung cancer between diabetic and non-diabetic patients using PET.
• To investigate the impact of diabetes on FDG uptake parameters and tumor-to-background ratios.

Main Methods:

• Dynamic FDG-PET scans were performed on 5 diabetic and 21 non-diabetic patients with untreated primary lung cancers.
• Standardized uptake value normalized for lean body mass (SUL) was measured in tumor, blood, muscle, and lung.
• A 3-compartment metabolic model analyzed FDG kinetics in tumors.

Main Results:

• Diabetic patients exhibited significantly decreased tumor SUL, tumor/blood, and tumor/muscle SUL ratios compared to non-diabetic patients (P < 0.02).
• The rate constant for FDG phosphorylation (k3) and influx constant (Ki) were significantly lower in diabetic patients (P < 0.02).
• A trend towards a decreased tumor/lung SUL ratio was observed in diabetic patients (P = 0.064).

Conclusions:

• FDG accumulation and tumor targeting are impaired in primary lung cancers of diabetic patients.
• Diabetes may reduce the diagnostic sensitivity of FDG-PET for detecting lung cancer.