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 p ositron emission tomography- (PET) 2[F-18]-fluoro-2-deoxy-D-glucose (F DG) imaging in extracranial head and neck cancers. Methods. Sixty pati ents with biopsy-proven cancers were studied using PET-FDG. Thirty-fou r 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). R esults. Four patients had unknown primary lesions. PET-FDG imaging loc ated the primary tumor in two of four patients, and magnetic resonance imaging (MRI) in none of four. In the remaining patients (staging), P ETFDG 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 pre sence or absence of lymph node involvement in 32 of 34 patients, and M RI in 31 of 34. PET-FDG imaging was helpful in evaluating tumor respon se to radiation therapy or laser excision. Ten patients evaluated for recurrent disease had biopsy-confirmed recurrences, and 7 had no recur rence. PET-FDG imaging results were positive for primary tumor recurre nce 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 demonst rated nodal involvement. PET-FDG results were negative for recurrent d isease in seven of seven patients, and MRI results were negative for r ecurrent disease in in four of seven. Conclusion. In this series, the authors found that PET-FDG is a useful diagnostic modality for evaluat ing the patient with an unknown primary, monitoring response to therap y, and in detecting recurrent tumors.