USE OF POSITRON EMISSION TOMOGRAPHY WITH FLUORODEOXYGLUCOSE IN PATIENTS WITH EXTRACRANIAL HEAD AND NECK CANCERS

Background. The purpose of this study was to evaluate the utility of positron emission tomography- (PET) 2[F-18]-fluoro-2-deoxy-D-glucose (FDG) imaging in extracranial head and neck cancers. Methods. Sixty patients with biopsy-proven cancers were studied using PET-FDG. Thirty-four patients were studied before therapy (staging), of which 15 patients received primary radiotherapy and serial PET-FDG imaging (monitoring). Seven patients with advanced disease had laser excision (monitoring), and 19 patients were evaluated for recurrent disease (recurrence). Results. Four patients had unknown primary lesions. PET-FDG imaging located the primary tumor in two of four patients, and magnetic resonance imaging (MRI) in none of four. In the remaining patients (staging), PETFDG imaging detected the primary tumor in 29 of 30 patients, and MRI in 23 of 30. In the staging group, PET-FDG imaging identified the presence or absence of lymph node involvement in 32 of 34 patients, and MRI in 31 of 34. PET-FDG imaging was helpful in evaluating tumor response to radiation therapy or laser excision. Ten patients evaluated for recurrent disease had biopsy-confirmed recurrences, and 7 had no recurrence. PET-FDG imaging results were positive for primary tumor recurrence in 9 of 10 patients, and MRI results were positive in 6 of 10. MRI results were negative for lymph node disease in one of these patients with recurrent primary tumor where PET-FDG imaging and biopsy demonstrated nodal involvement. PET-FDG results were negative for recurrent disease in seven of seven patients, and MRI results were negative for recurrent disease in in four of seven. Conclusion. In this series, the authors found that PET-FDG is a useful diagnostic modality for evaluating the patient with an unknown primary, monitoring response to therapy, and in detecting recurrent tumors.