Aims: Fluorodeoxyglucose positron emission tomography (FDG-PET) may detect residual or recurrent malignancy in patients with germ cell tumours (GCT) following chemotherapy. The objective of the present study was to evaluate the use of FDG-PET in the setting of advanced GCT, and to determine the influence of FDG-PET on subsequent patient management.
Methods: A computerized search of the patient database of the Department of Medical Oncology, Guy's Hospital, London, United Kingdom, and a manual search of medical records, were conducted. All male patients with metastatic or extragonadal GCT treated with chemotherapy between July 1996 and June 1999 inclusive were identified. Data from patients that had a PET scan following chemotherapy were analysed. Reported PET scan findings were compared with subsequent clinical management and patient outcome.
Results: A total of 30 patients with metastatic testicular GCT and three patients with extragonadal GCT were treated with chemotherapy. Of these, 15 patients (12 testicular; three extragonadal; 10 non-seminoma; and five seminoma) were investigated following chemo-therapy with at least one FDG-PET scan. Seven patients had two or more PET scans, and a total of 26 FDG-PET scans was performed. The most frequent indication for PET scan was evaluation of a residual mass (11 patients). Three patients had an FDG-PET to evaluate thymic prominence. Minimum follow up from first PET scan was 18 months. Three of 26 PET scans had false positive findings. Four PET scans yielded findings of equivocal significance with repeat PET scan recommended. Relapse of disease occurred in three patients; two of whom had normal previous PET scans and one had a previous equivocal result. PET had an impact on patient management in only one case where it 'prompted' surgical excision of a residual mass. Normal PET scans provided reassurance in patients with residual small masses but did not alter their subsequent -management.
Conclusions: A residual mass was the most common indication for PET. For the majority of patients PET did not have a discernible influence on clinical management. Oncologists should exercise caution in their interpretation of PET scan findings and guidelines for the appropriate use of PET in testicular cancer management need to be developed. Prospective trials are required to define the clinical role of PET in this setting.