Detection of cervical metastases with (11)C-tyrosine PET in patients with squamous cell carcinoma of the oral cavity or oropharynx: A comparison with (18)F-FDG PET

A disadvantage of 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG) positron emission tomography (PET) in head and neck cancer is that (18)F-FDG uptake is not specific to malignant tissue. To provide an alternative, radiolabeled amino acids such as L-1-[(11)C]-tyrosine ((11)C-TYR), were introduced because these are less avidly metabolized by inflammatory cells. In this prospective study, we compared both (11)C-TYR PET and (18)F-FDG PET performance in detecting cervical metastases in 27 patients with a squamous cell carcinoma (SCC) of oral cavity or oropharynx. (11)C-TYR PET sensitivity, specificity, and accuracy for detecting nodal metastases were 33%, 100%, and 81%, respectively. With respect to (18)F-FDG PET, these figures were 67%, 97%, and 89%, respectively. Neck metastases not detected by (11)C-TYR PET were camouflaged by high tracer uptake by salivary glands. Because of bilateral accumulation of (11)C-TYR in salivary glands, (11)C-TYR PET is not suitable to replace (18)F-FDG PET in staging SCC of oral cavity and oropharynx.