Current concepts and future perspectives in retroperitoneal soft-tissue sarcoma management.

Retroperitoneal soft-tissue sarcomas are complex, heterogeneous cancers requiring expert multidisciplinary care. They can occur anywhere in the retroperitoneal abdominal or pelvic space. Usually large at presentation they present particular challenges for both local treatment and systemic control. The most common adult subtypes are liposarcomas and leiomyosarcomas, followed by pleomorphic sarcoma/malignant fibros histiocytoma (an entity not always easily distinguishable from dedifferentiated liposarcoma). A variety of additional histotypes may also be observed, but are uncommon in the retroperitoneum, either because of intrinsic rarity or because they are usually found in other anatomic sites. The underlying biology varies according to the different histotypes. Pediatric subtypes mainly comprise extraskeletal Ewing sarcoma/pPNET and alveolar rhabdomyosarcoma. Surgery is critical for controlling these tumors and requires an aggressive approach. It may also provide useful palliation for patients with advanced slow-growing disease. Radiotherapy has acquired a definite position in attempting to reduce relapse, although prospective trials of adjuvant or neoadjuvant radiotherapy are needed. Chemotherapy has a limited role in the adjuvant setting for most forms of retroperitoneal sarcoma (excluding pediatric subtypes), but has an increasing role in advanced disease. Novel targeted therapeutic agents that target specific amplification or translocation products offer promise for subsets of these diseases.