New medical treatment options and strategies to assess clinical outcome in soft-tissue sarcoma.

Soft-tissue sarcomas (STSs) are a heterogeneous group of rare malignant tumors predominantly arising from the embryonic mesoderm. The mainstay of curative therapy is the complete surgical resection of all tumor manifestations with negative histological margins. However, up to 50% of patients will develop distant metastases during the course of their disease. The prognosis for those patients is grim with a 5-year overall survival of less than 10%. First-line systemic therapy with ifosfamide and doxorubicin results in overall response rates of only 20% by conventional response evaluation criteria in solid tumors (RECIST). However, stabilization of disease can be seen in a greater proportion. Therefore, the role of the RECIST criteria has been questioned and the implementation of new imaging studies (e.g., FDG-PET) has shown promising results in assessing early tumor response to therapy. Furthermore, a broader insight into the molecular pathways of sarcomagenesis has been gained in recent years, revealing intriguing targets for new therapeutic approaches (e.g., VEGF, VEGF receptor, IGF receptor, EGF receptor, mTOR and cyclin-dependent kinases). In addition, a growing body of evidence is linking specific genetic aberrations with clinical outcome (e.g., SYT-SXX translocation in synovial sarcoma). With further insight into the biology of STS and the combination of new treatment options with modern imaging techniques, we will most certainly be able to improve clinical outcome in patients with STS in the upcoming years.