I have been offered surgery straight away without a biopsy. Is that right?

Usually not. A percutaneous core needle biopsy carries a low risk and identifies the tumor type, which determines the extent of surgery and whether treatment before it is needed. Operating “blind” risks an incomplete operation.

The tumor has already been “shelled out.” What next?

The operative report, a review of the pathology by an experienced pathologist and a repeat CT are needed. If visible tumor remains, the MDT discusses a repeat radical operation; otherwise, surveillance or other treatment, depending on the sarcoma type.

Why remove a healthy kidney or bowel?

To remove the tumor with a layer of healthy tissue on all sides. If an organ lies tightly against the tumor or is invaded by it, preserving it may leave tumor cells behind and raise the risk of recurrence; the decision is based on imaging and findings during surgery.

Is radiotherapy needed?

Not for everyone. Preoperative radiotherapy is discussed individually; for most patients complete surgery remains the main treatment.

What happens if the sarcoma comes back?

It depends on the tumor type and the time since surgery. For a late liposarcoma recurrence that can again be removed completely, repeat surgery is worthwhile. Otherwise drug treatment is discussed.

Retroperitoneal sarcoma: biopsy and radical surgery

Retroperitoneal sarcomas are rare connective tissue tumors that grow in the space behind the abdominal cavity. There is plenty of room there, so by the time symptoms appear they are often large and lie against the kidney, bowel and major blood vessels. The main treatment is surgery, and the most important operation is the first one: the tumor must be removed completely, en bloc with the surrounding tissues, not “shelled out.” That is why a proper biopsy and a plan drawn up in a center that treats sarcomas regularly are needed before surgery.

Kateryna Valikhnovska, MD, surgical oncologist, during a laparoscopic operation — The laparoscopic stage of an operation: the lights in the operating room are dimmed because the surgeon works from the camera image on the monitor.

Types of retroperitoneal tumors

The most common retroperitoneal sarcoma is liposarcoma, well-differentiated or dedifferentiated, followed by leiomyosarcoma, solitary fibrous tumor and other rare types. The type determines the tumor’s behavior and risk of recurrence: liposarcomas tend to come back in the same place, while leiomyosarcomas more often spread to distant sites.

The cause of most sarcomas is unknown. Soft-tissue tumors of the retroperitoneum and pelvis can also be benign — schwannomas, paragangliomas, desmoids — but they cannot be told apart from sarcoma without a biopsy and an experienced pathologist.

Are there symptoms

For a long time there are none. Then an enlarging abdomen, a feeling of pressure or heaviness, a palpable mass and pain in the back or flank appear. A large tumor may compress the ureter, the veins — causing leg swelling — the bowel or nerves.

The tumor is often found by chance on ultrasound or CT.

Examinations needed

Contrast-enhanced CT of the abdomen, pelvis and chest — size, relationship to organs and vessels, lung and liver metastases; MRI for pelvic tumors.
Percutaneous core needle biopsy under CT or ultrasound guidance — from the back, not through the abdominal cavity. It carries a low risk and is usually needed to determine the tumor type and treatment plan; if a paraganglioma is suspected, it is done only after metanephrines have been tested.
Review of the biopsy by a pathologist specializing in sarcomas, with immunohistochemistry and molecular tests.
Split renal function assessment — in case a kidney has to be removed together with the tumor.

Open or laparoscopic biopsy is not performed: it spreads tumor cells through the abdominal cavity.

When surgery is possible

Surgery is recommended when the tumor can be removed completely and there are no distant metastases that would change the approach. Even a large tumor lying against several organs is often operable: neighboring organs are removed together with it if necessary.

In selected cases, mainly in an expert center or within a trial, chemotherapy or radiotherapy before surgery is discussed — neither is standard. For most patients, surgery comes first.

Pelvic tumors — soft-tissue sarcomas, desmoids, schwannomas — lie against the rectum, bladder, ureters, iliac vessels and nerves. For these, planning is especially careful: sometimes part of the bowel or bladder has to be removed, or the ureter or vessels reconstructed. Benign tumors, on the other hand, can often be removed while preserving the organs, and desmoids are often watched first — which is why diagnosis before surgery is so important.

If surgery is not possible now

With distant metastases or a tumor that cannot be removed completely, chemotherapy is the basis of treatment; targeted drugs are available for some types. For slow-growing well-differentiated liposarcoma, surveillance is sometimes chosen.

For recurrences, which are not uncommon in liposarcoma, repeat surgery is possible in patients whose tumor came back late and can again be removed completely.

How the operation is performed

The tumor is removed en bloc with the surrounding tissues, without opening it — if necessary with the kidney, a segment of bowel, part of a muscle, the pancreas or the spleen. The goal is to remove the tumor completely, without rupturing it, with a layer of surrounding tissue where possible, because this is how the risk of recurrence is reduced. “Shelling out” the tumor from its capsule, even if it seems technically easier, raises the risk of rupture and of leaving tumor cells behind.

If the tumor involves a major vein, the vein is resected and reconstructed if necessary. As a rule, the operation is performed open, because of the tumor’s size and the extent of resection.

A retroperitoneal sarcoma has only one true first operation. Everything that follows depends on how completely the tumor was removed then.

Kateryna Valikhnovska, MD, surgical oncologist

Recovery after surgery

Care follows the enhanced recovery after surgery (ERAS) protocol: early mobilization, early feeding, controlled pain relief. Recovery time depends on which organs were removed: after a nephrectomy, the function of the other kidney is monitored; after a bowel resection, nutrition.

After complete removal, adjuvant treatment is usually not needed; exceptions are considered by the MDT based on the tumor type and grade.

Follow-up

Follow-up is long: CT of the abdomen and chest every 3–6 months for the first years, then less often but for years, because recurrences, especially of liposarcoma, can occur late. The doctor sets the schedule according to the tumor type.

What to bring to the consultation

CT or MRI discs with reports — the discs themselves;
the biopsy report, tissue blocks and slides — for review by a sarcoma pathologist;
the operative report and pathology, if the tumor has already been removed;
blood tests with creatinine, kidney function data;
records of previous treatment.

If some materials are missing, that is no reason to postpone the consultation: some examinations can be done on site.

The consultation is free of charge. How it goes and how long it takes is described on the page “Oncologist Consultation”.