Current concepts in the management of retroperitoneal soft tissue sarcoma

Soft tissue sarcomas (STS) in the retroperitoneum are usually diagnosed at the late stages. Surgery is the mainstay of treatment. The technique of resection is standardized. After dissection of the retroperitoneal blood vessel, a retroperitoneal plane of dissection adjacent to the spinal foramina is established in between the layers of the abdominal wall. Complete resection with tumor-free resection margins is the primary goal in retroperitoneal sarcoma surgery. Preoperative assessment of pathoanatomical growth patterns with respect to retroperitoneal vascular structures--as well as to visceral and retroperitoneal organs--influences surgical strategies and thus the surgical outcome. Blood vessel replacement and a multivisceral en bloc approach improve the quality of resection. Blood vessel involvement is stratified in type I (arterial and venous involvement), type II (arterial involvement), type III(venous involvement), and type IV (no vascular involvement). Adjuvant and neoadjuvant treatment options (chemotherapy, targeted therapy, and radiation therapy) are currently being investigated. A prospective randomized phase III trial has shown a positive effect of neoadjuvant chemotherapy combined with regional hyperthermia in disease-free survival, response rate, and local control. Subsets of liposarcomas (myxoid and round cell type) are selectively responsive to novel drugs, such as trabectedin, a DNA-binding agent. Radiotherapy is applied in higher-grade locally advanced retroperitoneal STS. The optimal technique of delivering radiotherapy remains to be determined. The restricted number of patients with retroperitoneal STS and unsatisfying results in local tumor control and long-term survival indicate the need for multi-institutional cooperative studies. An international effort is required to improve the evidence level on multimodal treatment algorithms.