The usefulness of fluorine 18-labelled deoxyglucose positron emission tomography in the investigation of patients with cervical lymphadenopathy from an unknown primary tumor.
BACKGROUND: The usefulness of fluorine 18-labelled deoxyglucose positron emission tomography (PET) in the detection of unknown primary tumor in patients seen with malignant cervical lymphadenopathy thought to arise from a head and neck primary differs in the published reports to date. To assess the role of PET in this scenario in our institution, an audit was performed. METHODS: The records of 21 patients who met the clinical indication were reviewed. End points were the ability of PET to detect an unknown primary tumor and/or distant metastatic disease. RESULTS: In 8 of the 21 patients, PET detected a potential primary site, although none was unequivocally PET positive. One case was pathologically confirmed. In five patients the potential primary site identified on PET could not be confirmed: two had negative biopsies, and three had no clinical evolution in the PET-suspect area for at least 24 months after the initial study. In the remaining two patients, the potential primary site detected by PET was treated without biopsy. PET detected additional regional and/or distant disease that had not been previously documented in nine cases. CONCLUSIONS: PET did not add significantly to the detection of an occult primary tumor in patients who had already been comprehensively evaluated by clinical and radiologic investigations. It was of substantial benefit, however, in detecting unsuspected distant disease in patients with undifferentiated nodal histologic findings and helped in delineating regional disease in patients with N2 disease.