RESUMO
AIM: Assessment of the efficiency of 18F-FDG-PET (PET) for the detection of distant metastases and synchronous primary malignancies in patients with oral and oropharyngeal squamous cell cancer (OOSCC). PATIENTS, METHODS: Retrospective evaluation of PET studies of 422 patients with histologically confirmed OOSCC. 99 patients (23.5%) demonstrated a suspect distant finding of whom 84 could be interdisciplinary evaluated and consecutively confirmed or refuted by other diagnostic modalities or biopsy. RESULTS: In 74 of 80 evaluable cases, PET showed the primary tumour (92.5%). 26/84 suspect distant lesions (31%) showed by means of PET were confirmed to be malignancies (mean SUV 3.96; range 1.4-9.37). Main sites were the lung, the upper aerodigestive tract, and the gastrointestinal system. In the other 58 cases (69%), where the suspect lesions were confirmed as benign, mean SUV was 2.65 (range 0.7-6.5) (difference statistically significant). The SUV above which every suspect finding was proven to be of malignant condition was 6.5 (specificity 100%, sensitivity 38%, accuracy 81%). CONCLUSION: PET may have an important role in initial staging and the detection of distant metastases and synchronous primary malignancies. Setting a SUV threshold for determining malignancies can support interpretation. In borderline cases, however, interdisciplinary evaluation by means of other diagnostic modalities remains crucial.