Retroperitoneal sarcoma: the decisions you may face

Cancer page →Second-opinion finder →

3 treatment settings, 3 with more than one named option. Each section lays out the options the standard of care names, what each is for, the trials behind them with their recorded results, the side effects and cautions on record, and questions to ask. Built from the cancer page's standard-of-care rows; nothing here is advice for your case.

Early / localised

Primary, resectable

2 options

Single-stage complete en bloc resection with adjacent organs in a sarcoma reference centre, after core biopsy and multidisciplinary planning; preoperative radiotherapy not routine after STRASS, considered in well-differentiated and low-grade dedifferentiated liposarcoma.

The options, in plain words

IMRT / IGRT (modern external beam)Standard of care

IMRT and IGRT shape the radiation beam to the tumour's outline from multiple angles and check the patient's position with a scan before every session, so surrounding organs receive less dose. Fewer, larger doses are now standard in breast and prostate cancer, but a low-dose bath still spreads across normal tissue.

Conformal dose, fewer side effects
Hypofractionation saves visits

CT (computed tomography)Standard of care

A CT scan is a fast 3D X-ray that shows the size and shape of tumours and whether they have spread.

Fast, ubiquitous
Sub-millimetre resolution
Standard for RECIST response

Also referenced:FNCLCC grade (soft-tissue sarcoma)

The evidence behind it

STRASS (EORTC 62092)Phase 3 NCT01344018 2020266 peopleevidence 22
Tests IMRT / IGRT (modern external beam)
Primary resectable retroperitoneal sarcoma: preoperative radiotherapy (50.4 Gy) plus surgery versus surgery alone
Abdominal recurrence-free survival not improved by preoperative radiotherapy; possible benefit in liposarcoma subgroups only.

The main trade-offs on record

IMRT / IGRT (modern external beam)

Low-dose bath to normal tissue
Motion management

CT (computed tomography)

Anatomic only; cannot distinguish scar from live tumour
Radiation dose
Poor for brain, marrow, and small peritoneal disease

Questions to ask about this decision

Between IMRT / IGRT (modern external beam) and CT (computed tomography), which do you recommend for me, and what about my case would make you choose differently?
Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?
Why: The aim shapes how much side effect and disruption is worth accepting.
How closely do I match the people in STRASS (EORTC 62092), and does that change what the results mean for me?
Why: Trial populations are selected; age, fitness, prior treatment and biomarkers all affect how far results carry.
What happens if I delay, or decline this step for now? Is the decision reversible?
Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
For my situation (primary, resectable), which of the standard options do you recommend and why?
Why: Guideline options include: Single-stage complete en bloc resection with adjacent organs in a sarcoma reference centre, after core biopsy and multidisciplinary planning; preoperative radiotherapy not routine after STRASS, considered in well-differentiated and low-grade dedifferentiated liposarcoma.
How do the results of STRASS (EORTC 62092) apply to someone like me?
Why: Trial populations differ from individual patients; ask how closely you match.

Add these to your appointment list, or take the full question set for this cancer.

Early / localised

High-risk dedifferentiated liposarcoma or leiomyosarcoma

3 optionsCompare side by side →

Neoadjuvant chemotherapy within STRASS2 (doxorubicin-ifosfamide or doxorubicin-dacarbazine) or up-front surgery; no proven adjuvant therapy.

The options, in plain words

DoxorubicinApprovedCytotoxic chemotherapy (anthracycline)

The red chemotherapy drug from a soil bacterium that is still the backbone of treatment for sarcoma, lymphoma and breast cancer, limited by cumulative heart damage.

IfosfamideApprovedCytotoxic chemotherapy (alkylating agent)

Ifosfamide is an alkylating chemotherapy partnered with doxorubicin in sarcoma and with etoposide in Ewing sarcoma, given with a bladder-protecting drug.

DacarbazineApprovedAlkylating agent (triazene)

Dacarbazine is an older chemotherapy infusion. It was the standard treatment for advanced melanoma for decades and is the D in the ABVD regimen that cures most Hodgkin lymphoma.

The evidence behind it

No trial record is attached to this row yet. The trials tab lists what is recruiting and the landmark trials for this cancer.

The main trade-offs on record

Doxorubicin all recorded rates →

Cumulative dose: risk rises steeply above 400-550 mg/m² (see the anthracycline calculator).
Reduce by 50% for bilirubin 20-50 µmol/L and 75% for 50-85 µmol/L.

Questions to ask about this decision

Between Doxorubicin, Ifosfamide and Dacarbazine, which do you recommend for me, and what about my case would make you choose differently?
Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?
Why: The aim shapes how much side effect and disruption is worth accepting.
What happens if I delay, or decline this step for now? Is the decision reversible?
Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
For my situation (high-risk dedifferentiated liposarcoma or leiomyosarcoma), which of the standard options do you recommend and why?
Why: Guideline options include: Neoadjuvant chemotherapy within STRASS2 (doxorubicin-ifosfamide or doxorubicin-dacarbazine) or up-front surgery; no proven adjuvant therapy.
Am I a candidate for Doxorubicin, Ifosfamide, Dacarbazine, and what side effects should I expect?
Why: Knowing the expected toxicities helps you plan work, family, and supportive care.

Add these to your appointment list, or take the full question set for this cancer.

Advanced, first line

Recurrent or metastatic

4 optionsCompare side by side →

Repeat resection for slowly growing, unifocal recurrence; histology-driven chemotherapy (doxorubicin plus trabectedin for leiomyosarcoma, LMS-04; eribulin or trabectedin for liposarcoma); MDM2 inhibitor trials.

The options, in plain words

TrabectedinApprovedCytotoxic (DNA minor-groove binder)

A chemotherapy derived from a sea squirt, used with liposomal doxorubicin in relapsed ovarian cancer in Europe and for sarcomas.

EribulinApprovedSynthetic halichondrin B analogue (microtubule dynamics inhibitor)

A sea-sponge-derived chemotherapy that extended survival in heavily pretreated breast cancer and in liposarcoma, where almost nothing else had.

MDM2 inhibitorsPhase 3

Drugs that stop MDM2 destroying p53, reawakening the cell's guardian protein in tumours where p53 is intact but suppressed, such as some sarcomas and leukaemias.

Reactivates a non-mutated tumour suppressor
Biomarker-defined populations

PazopanibApprovedSmall-molecule kinase inhibitor (VEGFR/PDGFR/KIT)

Pazopanib is the only multi-kinase inhibitor approved for soft-tissue sarcoma (excluding fat-derived tumours), used after chemotherapy fails.

The evidence behind it

LMS-04 Phase 3 NCT02997358 2022150 peopleevidence 75
Tests Trabectedin
Metastatic or unresectable leiomyosarcoma, first line: doxorubicin plus trabectedin (then trabectedin maintenance) versus doxorubicin
Show survival figures (1)
Averages across everyone diagnosed, often years ago. Your stage, subtype, age, fitness and the treatment you receive matter more than the average, and the numbers are improving quickly.
Median PFS 12.2 vs 6.2 months (HR 0.41); overall survival also favoured the combination at later follow-up.
Progression-free survival (median) (months): Doxorubicin + trabectedin 12.2 vs Doxorubicin 6.2 · HR 0.41 · source

The main trade-offs on record

Trabectedin all recorded rates →

Alcohol: avoid (hepatotoxicity). Dexamethasone 20 mg before each dose protects the liver.
Reduce to 0.9 mg/m² in moderate impairment; avoid in severe.

Eribulin all recorded rates →

Possible QT prolongation. QT prolongation observed on day 8; monitor ECG in patients with heart failure, bradyarrhythmia or QT-prolonging drugs.
1.1 mg/m² (mild) or 0.7 mg/m² (moderate).
1.1 mg/m² for CrCl 15-49.

MDM2 inhibitors

Thrombocytopenia and gut toxicity
Only in TP53 wild-type tumours
No approval after several phase 3 trials

Pazopanib all recorded rates →

Take on an empty stomach (1 hour before or 2 hours after food).
Known QT prolongation. Avoid other QT-prolonging drugs where possible; check ECG and correct potassium and magnesium before and during treatment.
200 mg daily in moderate impairment; avoid in severe.

Questions to ask about this decision

Between Trabectedin, Eribulin, MDM2 inhibitors and the other options, which do you recommend for me, and what about my case would make you choose differently?
Why: Guidelines list several reasonable options; the choice turns on details of your tumour, your health and your priorities.
What is each option trying to achieve: cure, long control, or relief of symptoms, and over what time?
Why: The aim shapes how much side effect and disruption is worth accepting.
How closely do I match the people in LMS-04, and does that change what the results mean for me?
Why: Trial populations are selected; age, fitness, prior treatment and biomarkers all affect how far results carry.
What happens if I delay, or decline this step for now? Is the decision reversible?
Why: Some decisions can wait for a second opinion or a trial slot; others cannot. Knowing which is part of the choice.
For my situation (recurrent or metastatic), which of the standard options do you recommend and why?
Why: Guideline options include: Repeat resection for slowly growing, unifocal recurrence; histology-driven chemotherapy (doxorubicin plus trabectedin for leiomyosarcoma, LMS-04; eribulin or trabectedin for liposarcoma); MDM2 inhibitor trials.
Am I a candidate for Trabectedin, Eribulin, Pazopanib, and what side effects should I expect?
Why: Knowing the expected toxicities helps you plan work, family, and supportive care.
How do the results of LMS-04 apply to someone like me?
Why: Trial populations differ from individual patients; ask how closely you match.

Add these to your appointment list, or take the full question set for this cancer.

How to read this page. Options and results come from OnCo records with their sources; the settings are the standard-of-care rows on the cancer page, and the lines of therapy are on the sequencing grid. Where a setting names one path, the choice is usually about timing, trials and where to be treated: see expert centres. OnCo is orientation, not medical advice.