What Are Retroperitoneal and Abdominal Sarcomas?
Retroperitoneal sarcomas (RPS) are rare tumours arising in the retroperitoneal space — the area behind the peritoneum containing the kidneys, major vessels, adrenal glands and retroperitoneal fat. They represent 15% of all soft tissue sarcomas. The most common subtypes are liposarcoma and leiomyosarcoma. They typically grow to large sizes before causing symptoms.
Symptoms
Most patients present with a palpable abdominal mass. Additional symptoms include: abdominal discomfort or fullness, back pain (compression of lumbar plexus or kidney), leg swelling (venous compression), early satiety and weight loss. In advanced disease: haematuria, neurological symptoms from nerve involvement.
Diagnosis
CT scan: First imaging modality. Characterises tumour, assesses vascular involvement and identifies distant metastasis. MRI: Better characterisation of retroperitoneal fat tumours and neural involvement. PET-CT: For high-grade tumours to assess metastatic disease. Biopsy: Core needle biopsy is required for histological diagnosis before surgery in most cases. Must be performed carefully to avoid seeding and should not compromise future surgical resection.
Surgery: The Only Curative Treatment
Complete en-bloc resection is the standard treatment. This typically requires removal of adjacent organs sharing fascial planes with the tumour (kidney, colon, spleen, adrenal gland) even when not overtly involved — the "compartment surgery" approach. For liposarcoma this reduces local recurrence. Resection by an experienced team at a high-volume sarcoma centre is associated with significantly better local control.
Adjuvant Treatment
Radiotherapy: pre-operative radiotherapy may improve margin quality in selected cases. Chemotherapy: limited role for liposarcoma and leiomyosarcoma. May be considered for high-grade tumours or when R0 resection is not possible. Targeted therapy: trabectedin is approved for liposarcoma and leiomyosarcoma second-line.
R0 Is Not Decided by the Tumour, It Is Decided by the Team
The survival figures for retroperitoneal sarcoma are worth restating: roughly 50 to 60% at 5 years with a complete resection, against 10 to 20% when disease is left behind. That gap is not created by the subtype or the size, but by whether the surgeon manages to remove everything en bloc at the first attempt.
In the retroperitoneum that frequently means resecting adjacent structures in the same procedure: kidney, colon, tail of pancreas, spleen or vascular segments. A team that is not prepared for this tends towards a more conservative resection, which leaves a positive margin and compromises the result.
The key question before surgery is therefore not "which sarcoma do I have?" but "can this team resect en bloc whatever turns out to be necessary?". It requires specific volume in retroperitoneal sarcoma, the capability for multivisceral resection, and oncovascular backup should a vessel need reconstruction.
If the sarcoma has already been operated on and has recurred, salvage surgery remains possible in selected cases, although every reoperation reduces the available margin.
Do you have an abdominal or retroperitoneal sarcoma awaiting surgery? This is the moment when a second opinion changes the outcome most, because the first operation is the one that decides. We review the imaging and tell you whether the planned resection goes far enough. Request an assessment.