Abstract
1735
Objectives: To evaluate the role of FDG PET in head and neck squamous cell carcinoma of unknown primary.
Methods: A retrospective review of our PET archive was used to select patients with a history of a neck mass. Patients with squamous cell carcinoma on excisional or needle biopsy who were determined after ENT workup to have a probable but unknown head and neck primary were selected. Endoscopy was not performed routinely in these patients prior to PET examination. Often PET was the primary imaging modality utilized. PET exams read as either “suspicious”, “indeterminate” or “positive” on initial PET reading were considered PET positive for this study. PET results were correlated with biopsy and clinical follow-up results
Results: Forty-nine patients were identified that met criteria. In a single case a subcentimeter primary lung squamous carcinoma,presumed primary, was identified . In 4 patients with positive PET findings, no further work-up was initiated and patients were treated presumptively. The remaining forty-four patients underwent PET or surgical directed biopsies in the head and neck. Twenty-four of these cases were positive on PET for primaries of the head and neck. Of these, 20/24 were positive at biopsy and 4/24 were negative at biopsy. These four negatives were thereafter negative clinically or radiographically with a mean follow time 16 months. Twenty cases were negative on PET. Subsequent biopsies were negative in 19 cases. Mean follow up was 23 months. The sensitivity of PET in detecting head and neck primary was 95%. Specificity was 83%.
Conclusions: In this retrospective study of 49 patients, 18F-FDG PET had a sensitivity of 95% and specificity of 83% in detecting primary tumor of the head and neck in patients with squamous cell carcinoma of unknown primary.
- Society of Nuclear Medicine, Inc.