Retroperitoneal sarcoma (RPS) is a rare type of tumor found in the abdomen. Surgery is the main way to treat it. This study collects information from patients with RPS who have surgery. It aims to understand more about the disease and improve treatments. The study will look at how long patients live after surgery and if the cancer comes back.

RPS is tricky because it grows near important body parts, making it hard to remove completely. Different types of RPS have different risks of coming back. Some types, like liposarcomas, often return, while others, like solitary fibrous tumors, usually don’t.

This study follows patients for several years to see how they do after surgery. It also looks at whether other treatments like radiation or chemotherapy help. The study collects data from many hospitals worldwide to learn the best ways to treat RPS.

• This study involves multiple hospital visits for scans.
• Participants must be over 18 and have had surgery for RPS.
• Patient information is kept private and not shared without consent.