Cancer of unknown primary origin - Utility of 18F-FDG PET/CT

1109 Learning Objectives 1. Provide a concise overview regarding the clinical problem of cancer of unknown primary origin. 2. Briefly review non-imaging and imaging techniques usually employed for the evaluation of unknown primary tumors. 3. Summarize and discuss the current data on the utility of 18F-FDG PET in the investigation of patients who present with cancer of unknown primary origin (highlighting possible differences in patients with cervical lymph node metastasis versus other types of localization). 4. Provide illustrative figures of 18F-FDG PET in this patient population. Summary: Patients presenting with metastatic carcinoma of unknown origin represent a distinct clinical challenge. If a primary tumor is identified, appropriate, cancer specific treatments could be administered. Although a search for the primary tumor by various non-imaging and imaging procedures is usually undertaken, it reveals a primary lesion only in the minority of patients. Recently published recommendations from an expert panel state that 18F-FDG PET should routinely be used in the evaluation of patients with unknown primary cancer since it may be able to detect primary lesions not identified by conventional work-up. Our presentation will not only provide an up-to-date overview of the current evidence regarding the use of FDG PET in patients with unknown primary cancer, but also discuss remaining questions and potential directions for future research.