[Positron emission tomography as a tool for early prediction of therapy outcome in soft tissue sarcoma]

We used 2-deoxy-2-[(18)F] fluoro-D-glucose (FDG) positron emission tomography (PET) to evaluate the FDG uptake in patients with soft tissue sarcoma (STS). Treatment effect was assessed with regard to prediction of therapy outcome.

This evaluation includes 35 patients with high risk STS receiving chemotherapy consisting of doxorubicin and ifosfamide (AI-G regimen) or etoposide, ifosfamide and doxorubicin (EIA regimen). Patients were examined using PET prior to onset of therapy and after completion of the first cycle of AI-G and after two cycles of EIA chemotherapy, respectively. Restaging according to RECIST was performed after six cycles of AI-G or four cycles of EIA chemotherapy and served as reference.

Clinical outcome of 35 evaluable patients was as follows: two patients with no evidence of disease (NED), eleven with partial remission (PR), 17 with stable disease (SD), and five patients with progressive disease (PD). A difference regarding progression-free survival for patients with a decrease in SUV (responders) in comparison to patients with an increase or stable SUV (non-responders) could be demonstrated (p = 0.0943).

On the basis of these data, prediction of chemo-sensitivity of the tumour and moreover of the therapy outcome might be possible.