Purpose: We compared 3'[F-18]fluoro-3'-deoxythymidine (FLT) positron emission tomography (PET) and 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) for PET visualization of head and neck squamous cell cancers (HNSCCs) and evaluated which might better reflect proliferative activity as indicated by the Ki-67 index.
Procedures: A total of 43 patients with HNSCCs were examined with FLT-PET and FDG-PET. The PET images were evaluated qualitatively for regions of focally increased metabolism and for semiquantitative analysis the maximum standardized uptake value (SUV) was calculated.
Results: For depiction of primary tumours, the sensitivity of both approaches was 100%. The mean (± SD) SUV for FLT (5.65 ± 2.96) was significantly lower than that for FDG (10.9 ± 4.91; p < 0.0001). No significant differences were found for the T category. However, the mean (± SD) FLT SUV was significantly higher in poorly than in well-differentiated tumours (6.49 ± 3.13 vs. 4.2 ± 2.08; p < 0.04). Similarly, FDG SUVs in poorly and moderately differentiated tumours (12.72 ± 4.8 and 11.46 ± 4.64) were significantly higher than in well-differentiated tumours (7.45 ± 3.51; p < 0.004 and p < 0.02). No significant correlation was observed with the Ki-67 index for either.
Conclusion: FLT-PET showed as high a sensitivity as FDG-PET for the detection of primary HNSCC lesions, although uptake of FLT was significantly lower than that of FDG.