POSITRON-EMISSION-TOMOGRAPHY IN THE EVALUATION OF THE N0 NECK

The presence of cervical lymph node metastasis in patients with head a nd neck cancer is associated with an unfavorable prognosis. Reports va ry as to whether various conventional radiographic studies, such as co mputed tomography (CT) and magnetic resonance imaging, confer an advan tage over physical examination in the patient without clinical finding s of cervical metastasis (NO). Positron emission tomography (PET) is a functional imaging modality that has recently been used for head and neck neoplasms. The use of PET in the evaluation of the NO-staged neck in 14 consecutive patients with squamous cell carcinoma (SCC) of the upper aerodigestive tract is reported. Seven patients (50%) undergoing 13 neck dissections had pathologic evidence of disease. PET scans wer e positive in five patients with pathologically confirmed cervical met astasis. PET scans were negative in seven patients (11 neck dissection s) with no pathologic evidence of disease. PET scans were positive for unilateral cervical metastasis in two of three patients with involvem ent of a single lymph node. PET scans were positive in two of three pa tients with more than two lymph nodes involved, PET had an accuracy of 100% in the eight patients with SCC of the oral cavity. In patients w ith oropharyngeal or hypopharyngeal carcinoma PET localized cervical m etastasis in two of four patients with neck metastasis, In the patient with an NO-staged neck on clinical examination, PET was found to have an overall sensitivity of 78%, specificity of 100%, positive predicti ve value of 100%, negative predictive value of 88%, and accuracy of 92 %. CT demonstrated sensitivity of 57%, specificity of 90%, positive pr edictive value of 80%, negative predictive value of 75%, and accuracy of 76%. PET showed a trend in increased accuracy (P = 0.11) over CT. P ET appears to be a promising diagnostic aid that may be applied when e valuating the NO-staged neck, especially for SCC of the oral cavity.