DETECTION OF LOCAL RECURRENCE OF SOFT-TISSUE SARCOMA WITH POSITRON EMISSION TOMOGRAPHY USING [F-18] FLUORODEOXYGLUCOSE

Background: It is often difficult to detect a local recurrence of soft -tissue sarcomas due to disturbance of the normal anatomy by previous surgery and radiotherapy. The aim of this study was to assess the valu e of positron emission tomography (PET) with [F-18]fluoro3-deoxy-D-glu cose (FDG) for detecting local recurrences. Methods: In the period 199 2-1995, 17 patients with proven or suspected local recurrence of soft- tissue sarcoma were examined using FDG-PET. Fifteen of these patients were ultimately proven to have a recurrence. Results: Recurrence was v isualized in 14 patients (93%). Small tumors (maximum diameter 0.5 cm) were as easily visible as large lesions (maximum diameter 20 cm). In one patient the PET scan was positive, but the recurrence could not be proven histologically. Recurrence was proven 1 year later. A recurren t low-grade liposarcoma was not visualized. The two patients with beni gn lesions had a negative PET scan. The mean glucose metabolic rate wa s calculated to be 13.2 mu mol/100 g/min (range 1.9-28.4). A correlati on was found between the histological malignancy grade and the metabol ic rate (p < 0.05; Kruskal-Wallis). Conclusion: PET with FDG is a usef ul addition to the diagnostic armamentarium for detecting local recurr ence of soft-tissue sarcomas and provides an indication of the maligna ncy grade of the recurrent lesion.