Staging with 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) for nonseminomatous germ cell tumor (NSGCT): The Peter MacCallum Cancer Centre experience

Abstract

e16140 Background: We retrospectively evaluated our single institution experience using FDG-PET as part of initial assessment of stage I/II NSGCT. Previous studies by de Wit et al and the TE22 trial concluded that there was a very limited role for PET staging in NSGCT. Despite these results, PET continues to be utilised in our center. Methods: With local ethics approval, the PET center database at Peter MacCallum Cancer Centre (PMCC) was used to identify a series of 26 patients with NSGCT who underwent FDG-PET as part of staging investigations between 1998 and 2008. Demographic and clinical information was collected using electronic and paper medical records. Histological samples were reviewed if additional information was required. Results: Lymphovascular invasion (LVI) was present in 10 (38%) of orchiectomy specimens. 15 patients had stage I disease on both CT and PET. PET upstaged 7 patients from stage I to stage II disease, and all upstaged patients received systemic chemotherapy (3 cycles BEP). 1 patient with stage I disease on PET and CT received adjuvant chemotherapy (2 cycles EP). 3 patients with LVI and stage 1 disease on CT and PET underwent surveillance. With median follow-up of 33 months (range 1–94), all patients were alive without disease recurrence, although 1 patient was treated for a second primary NSGCT. Conclusions: Using PET images, we were able to identify patients with low volume metastatic disease and achieve 100% relapse-free survival rates. Despite the small sample size, these results are promising and are better than expected based on published data. This might be explained by the quality of the PET imaging, including attenuation correction and combined CT/PET for enhanced sensitivity interpreting retroperitoneal disease. Further evaluation of PET is warranted, particularly in patients with equivocal CTs or with the high-risk feature of LVI. [Table: see text] No significant financial relationships to disclose.