Approach Considerations
Three main modalities exist:
1. Surgery - remains the most important modality and the importance of a complete excision is critical
2. Chemotherapy - pre- or post-surgery
3. Radiation - also pre- or post-surgery
Medical Care
Chemotherapy has been shown to be active in these tumors, but its role needs to be defined in clinical trials. Italian studies showed that the use of neoadjuvant multiagent chemotherapy could decrease the size of the tumor and allow a complete resection. [23] The role of post-operative chemotherapy has not been defined.
Adult studies have shown some promise in using trabectedin, an unconventional alkylating agent derived from Caribbean sea squirt, which showed a 45% reduction in disease progression compared to dacarbazine in a Phase III study in patients with advanced liposarcoma and leiomyosarcoma who had failed prior therapy. [24] Unfortunately trabectedin as a single agent has not shown a benefit in pediatric trials. [25]
With better understanding of molecular biology of liposarcoma, targeted therapies have been identified. MDM2 inhibitors such SAR40538 and CDK4 inhibitors such as NVP-LEE011 have shown promise. [26]
Postoperative radiotherapy may be administered.
Surgical Care
Surgical objectives include obtaining an accurate histologic diagnosis, minimizing the chance of local recurrence, achieving the best possible functional and anatomic result, and maximizing the probability of survival. Surgery should be performed at a children's cancer center with significant experience dealing with these rare tumors.
Open biopsy must be meticulously performed to avoid hematoma, tumor cell spillage, and postoperative infection. The incision must be oriented so that the biopsy site can be completely encompassed in the definitive resection. A longitudinal incision parallel with the fiber direction of the underlying muscle is used. Under ideal conditions, the surgeon performing the definitive resection also should perform the initial biopsy. Sometimes, performing the incisional biopsy and resection is possible during the same procedure, provided that the frozen section is definitive.
The 3 main techniques of surgical resection used in patients with liposarcoma include simple excision, wide en bloc resection, and amputation. The type of resection used is determined by the tumor's histology and by the anatomic findings at the time of surgery. [27]
If the lesion appears to be grossly and histologically consistent with lipoma or well-differentiated liposarcoma, simple excision is acceptable.
If the mass contains areas suggestive of low-grade liposarcoma with clear margins, simple marginal excision can be curative. When evidence suggesting high-grade liposarcoma is present, either a wider resection of the tumor bed may be performed or adjuvant radiotherapy may be added.
If preoperative studies (CT scanning, MRI, biopsy specimen analysis) suggest a high-grade lesion, either wide en bloc resection or amputation can be planned. Avoid shelling out a high-grade tumor because microscopic disease is left behind. In patients in whom amputation is under serious consideration (either as an initial procedure or following a limb-sparing operation), preoperative education is imperative.
In upper extremity tumors, axillary dissection is not performed unless the nodes feel abnormal.
Consultations
For lesions in which malignancy is strongly suspected or in which a previous incisional biopsy has revealed liposarcoma, consultation with pediatric oncologist is recommended prior to the definitive surgical procedure.
Adjuvant therapy may be indicated in patients in whom excision is incomplete or when close margins are noted along with concern about microscopic residual disease. Consultation with a radiation oncologist is recommended.
Activity
Consultation with a physical therapist and referral for rehabilitation may be appropriate, depending on the site of the primary and the degree of surgical resection performed.
