20511 Background: We used 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography (FDG) studies to evaluate the FDG metabolism kinetics in patients (pts.) with high risk soft tissue sarcomas receiving an induction or neoadjuvant chemotherapy. The treatment effect was assessed with regard to the prediction of therapy outcome. Methods: The ongoing evaluation includes 25 pts. with high grade soft tissue sarcoma with different histologies: 14 pts. received an induction chemotherapy consisting of adriamycin 75 mg/m2/day 1 and ifosfamide 1500 mg/m2/day 1–4 (AI-G regimen, six cycles) prior to peripheral blood stem cell transplantation, and 11 pts. were treated with pre-operative chemotherapy consisting of etoposide 125 mg/m2/day 1+4, ifosfamide 1500 mg/m2/day 1–4 and doxorubicin 50 mg/m2/day 1 (EIA regimen, 4 cycles). Pts. were examined prior to onset of therapy and after completion of the first cycle of AI-G and after two cycles of EIA chemotherapy, respectively. The restaging data of 21 patients (11 pts with AI-G and 10 patients with EIA treatment) served for reference. Restaging was performed using computed tomography and magnetic resonance tomography after six cycles of AI-G or four cycles of EIA chemotherapy. Results: 21 pts. were evaluable by the time of data evaluation. According to RECIST criteria, clinical outcome was as follows: 3 pts. showed no evidence of disease (NED), 6 partial remissions (PR), 5 stable diseases (SD), and 7 pts. with progressive disease (PD). Due to the small number of pts., we dichotomized the data in pts. with NED/PR (n = 9) and pts. with SD/PD (n = 12). Median average standard uptake value (SUV) prior therapy was 5.4 in comparison to 4.1 after chemotherapy. Median maximum SUV was 8.3 prior to chemotherapy in comparison to 6.6 following therapy. We used discriminant analysis and four predictor variables, namely the average and maximum SUV of both the baseline and the follow-up study to classify the pts. into responders and non-responders. Discriminant analysis revealed a correct classification rate of 70 %. Conclusions: On the basis of these data, prediction of chemo-sensitivity of the tumor and moreover of the therapy outcome might be possible. No significant financial relationships to disclose.
Clinical implications of determination of safe surgical margins by using a combination of CT and 18FDG-positron emission tomography in soft tissue sarcoma
