[The role of PET-CT in evaluation of recurrence and metastasis of head-and-neck tumor after definitive treatment].

OBJECTIVE: To explore the significance of 8F-FDG PET-CT in the diagnosis of the recurrence and metastasis of head-and-neck tumor after definitive treatment. METHOD: Forty-two patients having received definitive treatment for head-and-neck tumor of whom the tumor could not be identified clinically underwent 18F-FDG PET-CT examination. Follow-up data could be obtained for all foci identified on PET-CT images. PET-CT and CT accuracy was compared on the basis of follow-up and histopathologic findings. RESULT: A total of 103 foci were noted on PET-CT images. Identified by follow-up data, the sensitivity, specificity and accuracy were 92.55%, 42.11% and 84.07% respectively for CT examination, and 100.00%, 52.63%, and 92.04% for PET-CT respectively. The sensitivity and accuracy of PET-CT were significantly higher than those of CT (P < 0.05 or P < 0.01), whereas the difference in specificity between the results of these two groups was not significant (P > 0.05). CONCLUSION: The major benefits of FDG PET were that it differentiates scar and relapse, as well as detects LN and distant metastasis. Detailed clinical information and inclusion of results of morphological diagnostics are prerequisites for PET-CT final image interpretation, while scans should not be performed less than 6 weeks after definitive treatment.