Assessment for Staging of Head and Neck Cancers by FLT PET

Abstract

Objective: Investigate the feasibility of using FLT PET to detect head and neck squamous cell cancer (HNSCC) and to compare the diagnostic efficacy with that of FDG PET in evaluation of the nodal and distant metastatic staging.

Method: Patients with histopathologically proven HNSCC underwent FLT PET and FDG PET performed at 60 min after radiotracer injection. 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 tumors, the sensitivity of both approaches was 100%. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for lymph node staging on a per-patient basis were 71, 95, 94, 72, and 81%, respectively, with FLT PET and 79, 89, 90, 77, and 84%, respectively, with FDG PET. One of 2 distant metastases was detected with FLT and FDG PET. Although FLT PET had no false-positive result for M staging, FDG PET showed three false-positive results owing to physiological bowel activity and/or inflammation.

Conclusion: FLT PET was found to have high sensitivity for depiction of primary tumors despite a lower FLT SUV than FDG. FLT PET showed better specificity and positive predictive values for N staging than FDG PET. Further studies are needed to predict and evaluate tumor response to therapy by FLT PET.