FDG-PET for germ cell tumors

摘要

abstract_textpPositron emission tomography employing 18-fluorodeoxyglucose (FDG-PET) adds a metabolic functional dimension to the morphologic diagnostics of computed tomography (CT), with elevated glucose metabolism as a parameter of tumor activity. Because the sensitivity of FDG-PET is higher than that of CT for primary staging of germ cell tumors, FDG-PET could be used instead of CT. No data exist for its use in seminomas, but additional FDG-PET may be useful under certain conditions in nonseminomatous germ cell tumors (NSGCT) when the physician must decide between different therapeutic strategies such as "watch-and-wait" or adjuvant chemotherapy. Several studies have investigated the viability of residual masses in NSGCT. For special clinical questions, FDG-PET is able to offer additional information, which should be interpreted carefully within the clinical context because mature teratomas do not show elevated glucose metabolism and cannot be distinguished from necrotic masses. Moreover, inflammation or granulomatous diseases may increase false-positive results. In patients with seminomas and residual tumours, FDG-PET allows for therapeutic decisions; for example, resection can be avoided in residual masses larger than 3 cm, without FDG accumulation. Only limited data are available concerning the use of FDG-PET in patients with tumor marker elevation without morphological evidence of relapse or early prediction of therapeutic outcome, but FDG-PET may be helpful for further therapeutic decision making./p/abstract_text