Management of multifocal and metastatic retroperitoneal sarcoma: an updated consensus approach from the transatlantic australasian retroperitoneal sarcoma working group (TARPSWG).

[BACKGROUND] Retroperitoneal sarcoma (RPS) encompasses a heterogenous group of rare malignancies that develop in the back of the abdomen. For localized primary disease, the mainstay of treatment is surgery. Beyond the primary site, patterns of disease manifestation vary by histologic type and include visceral organ metastasis, as well as intraabdominal multifocal disease. Although cure is extremely rare, some patients may still derive significant benefit from treatment.

[METHODS] A comprehensive literature search was performed and international, key opinion leaders for RPS met together to discuss principles of practice for multifocal and metastatic disease, summarized in 45 statements, each given a level of evidence and grade of recommendation.

[RESULTS] Patients should be evaluated in a multidisciplinary sarcoma center with experience in RPS and recognition of histologic type is critical to guide management. After pretreatment assessment that includes imaging and pathology review, the goals of treatment should be clarified upfront and aligned with the anticipated ability for the patient to tolerate treatment. Disease biology (e.g., disease-free interval) should be thoroughly understood. Treatment modalities can include a combination of surgery, non-surgical local therapy (radiation therapy, percutaneous tumor ablation and embolization) and systemic therapy.

[CONCLUSIONS] This updated consensus document gives comprehensive and practical clinical guidance to providers for the management of multifocal and metastatic RPS. The current document also serves as the foundation for future clinical and translational investigation, as we continue to optimize patient care in these complex and challenging cases.