Treatment for Retroperitoneal Dedifferentiated Liposarcoma
Complete surgical resection with en bloc removal of the tumor and adherent structures is the primary curative treatment for retroperitoneal dedifferentiated liposarcoma, and should be performed at a high-volume sarcoma center by a surgeon with specific expertise in this disease. 1, 2
Preoperative Evaluation and Planning
Mandatory preoperative core needle biopsy (14-16 gauge) should be performed via a retroperitoneal approach (not transperitoneal) to confirm the diagnosis and guide treatment decisions, as needle track seeding risk is minimal. 1 Open or laparoscopic biopsies must be avoided. 1
Comprehensive imaging with contrast-enhanced CT of chest, abdomen, and pelvis is standard for staging, with MRI as an option for pelvic tumors. 1 Critical evaluation should specifically identify the dedifferentiated component versus well-differentiated areas, as this distinction is essential for surgical planning. 1
All cases must be reviewed by a multidisciplinary sarcoma tumor board before treatment initiation. 1
Surgical Approach
The surgical goal is macroscopically complete (R0) resection in a single en bloc specimen, which often requires resection of adherent organs even if not overtly infiltrated. 1, 2 This commonly necessitates:
- Ipsilateral nephrectomy 1, 2
- Hemicolectomy 1, 2
- Psoas fascia/muscle resection 1, 2
- Distal pancreatectomy/splenectomy on the left side 1
Grossly incomplete resection is potentially harmful and should be avoided, as median survival drops from 103 months with complete resection to only 18 months with incomplete resection. 2 Incomplete resection can only be considered palliative in carefully selected patients. 1
Preservation of specific organs (kidney, pancreatic head, liver, neurovascular structures) should be considered on an individualized basis, requiring specific disease expertise. 1 Preoperative/intraoperative tumor rupture is associated with poor prognosis. 1
Role of Radiation Therapy
Preoperative radiation therapy is NOT recommended for resectable high-grade dedifferentiated liposarcoma, as a randomized trial showed no improvement in recurrence-free survival or overall survival in this subgroup. 1 However, for low-intermediate grade dedifferentiated liposarcoma, preoperative RT can be discussed as signs of efficacy were observed in this subset. 1
If positive margins occur postoperatively, radiation can be considered with 50 Gy external beam RT plus boost doses of 16-18 Gy for microscopically positive margins (if normal tissue can be adequately spared with tissue displacement). 1 For intra-abdominal/retroperitoneal tumors, external beam RT may be decreased to 45 Gy, and a boost may not be possible if potential radiation morbidity is high. 1
Role of Chemotherapy
The evidence for chemotherapy in retroperitoneal dedifferentiated liposarcoma is limited and does not show clear survival benefit. 2 An analysis of 8,653 patients revealed worse overall survival in surgically resected patients receiving chemotherapy versus surgery alone (40 vs 52 months). 2
Neoadjuvant chemotherapy is currently under investigation and can be considered for:
- Technically unresectable/borderline resectable tumors that could be surgically converted by downsizing 1
- Selected cases after careful multidisciplinary review 1
While some case reports show dramatic responses to doxorubicin/ifosfamide (AI) regimens 3, 4, these remain exceptional cases rather than standard practice.
Palbociclib is mentioned as an option specifically for well-differentiated/dedifferentiated liposarcoma in the systemic therapy setting. 1
Recurrent Disease
Surgery for local recurrence should be considered on an individualized basis within a specialist sarcoma MDT, evaluating prognostic factors including age, histological subtype, tumor grade, multifocality, disease-free interval, and previous treatment. 1
Dedifferentiated liposarcomas tend to recur locoregionally, with most recurrences occurring within 5 years of treatment. 1 Local recurrence was seen in 75% of patients without neoadjuvant radiochemotherapy versus 33% with neoadjuvant radiochemotherapy in one series. 4
Critical Pitfalls to Avoid
- Transperitoneal biopsy approach increases contamination risk 1
- Attempting resection at non-specialized centers significantly compromises outcomes 1, 2
- Incomplete resection is associated with dramatically worse survival and should be avoided through careful preoperative planning 2
- Interruption of postoperative treatment may lead to unfavorable prognosis 5
- Vascular invasion is a poor prognostic factor requiring careful surgical planning 5