FDG--a marker of tumour hypoxia? A comparison with [18F]fluoromisonidazole and pO2-polarography in metastatic head and neck cancer.
OBJECTIVE
Experimental data suggest that the accumulation of [(18)F]fluorodeoxyglucose (FDG) in malignant tumours is related to regional hypoxia. The aim of this study was to evaluate the clinical potential of FDG positron emission tomography (PET) to assess tumour hypoxia in comparison with [(18)F]fluoromisonidazole (FMISO) PET and pO(2)-polarography.


METHODS
Twenty-four patients with head and neck malignancies underwent FDG PET, FMISO PET, and pO(2)-polarography within 1 week. Parameters of pO(2)-polarography were the relative frequency of pO(2) readings <or=2.5 mmHg, <or=5 mmHg and <or=10 mmHg, respectively, as well as the mean and median pO(2).


RESULTS
We observed a moderate correlation of the maximum standardised uptake value (SUV) of FDG with the tumour to blood ratio of FMISO at 2 h (R=0.53, p<0.05). However, SUV of FDG was similar in hypoxic and normoxic tumours as defined by pO(2)-polarography (6.9+/-3.2 vs 6.2+/-3.0, NS), and the FDG uptake was not correlated with the results of pO(2)-polarography. The retention of FMISO was significantly higher in hypoxic tumours than in normoxic tumours (tumour to muscle ratio at 2 h: 1.8+/-0.4 vs 1.4+/-0.1, p<0.05), and the FMISO tumour to muscle ratio showed a strong correlation with the frequency of pO(2) readings <or=5 mmHg (R=0.80, p<0.001).


CONCLUSIONS
These results support the hypothesis that tumour hypoxia has an effect on glucose metabolism. However, other factors affecting FDG uptake may be more predominant in chronic hypoxia, and thus FDG PET cannot reliably differentiate hypoxic from normoxic tumours.
Zimny
Michael
M
Department of Nuclear Medicine, University Hospital Aachen, Aachen, Germany. zimny@nuklearmedizin-hanau.de
Gagel
Bernd
B
DiMartino
Ercole
E
Hamacher
Kurt
K
Coenen
Heinz H
HH
Westhofen
Martin
M
Eble
Michael
M
Buell
Ulrich
U
Reinartz
Patrick
P
D014408:Biomarkers, Tumor / Q000378:metabolism; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D000860:Hypoxia / Q000000981:diagnostic imaging / Q000378:metabolism*; D008920:Misonidazole / Q000031:analogs & derivatives* / Q000378:metabolism; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging; D010100:Oxygen / Q000378:metabolism*; D011048:Polarography; D049268:Positron-Emission Tomography; D012015:Reference Standards
D014408:Biomarkers, Tumor; C031843:fluoromisonidazole; D019788:Fluorodeoxyglucose F18; D008920:Misonidazole; D010100:Oxygen