False-positive fluorodeoxyglucose positron emission tomography results after chemotherapy in patients with metastatic seminoma

In patients with metastatic seminoma who received chemotherapy, FDG-PET is a valuable tool to evaluate whether the residual mass contains viable tumor tissue or only necrosis. Nevertheless, because of FP results, a subgroup is overtreated with consecutive mortality or morbidity. We suggest an alternative therapy algorithm. In case of a positive result on FDG-PET studies, at least 8 weeks after the end of the chemotherapy, only a minority require surgery (e.g., patients with ureteral compression, patients with high risk of recurrence, or patients with unclear initial histology). In all other cases, we suggest a repeat FDG-PET study at least 6 weeks after the initial PET scan. Only in cases of increased SUVs or progressive disease histology should be obtained, all others can be on active surveillance.