IMAGING METASTATIC TESTICULAR GERM-CELL TUMORS WITH (18)FDG POSITRON EMISSION TOMOGRAPHY - PROSPECTS FOR DETECTION AND MANAGEMENT

The aim of this study was to investigate the role of positron emission tomography (PET) with [F-18]fluoro-2-deoxyglucose ((18)FDG) in metast atic testicular germ cell tumours. Twenty-one patients with stage II-I V testicular germ cell tumours were imaged by PET with a multiwire pro portional chamber PET system and (18)FDG. Avid (18)FDG uptake was seen in metastatic disease from primary seminoma and malignant teratoma. N ormal tissue uptake was seen in differentiated teratoma or necrotic, f ibrotic tissue. (18)FDG standard uptake values and tumour to normal ti ssue ratios were 6.0+/-1.4 and 1.7+/-0.4 (mean+/-1SD), respectively, f or malignant tissue. Reduction of (18)FDG tumour to normal tissue rati os from pre-treatment to on-treatment scans was predictive of response (n=3). No significant reduction in (18)FDG uptake was seen in patient s not responding to therapy (n=2). These results suggest a role for (1 8)FDG PET in the detection and management of metastatic testicular ger m cell tumours.