Assessment of Helical Tomotherapy Radiotherapy (54 Gy) Followed by Surgery in Retro-peritoneal Liposarcoma

Retro peritoneal liposarcomas are rare (less than 15% of sarcomas) whose prognosis is locoregional.

In the treatment of retroperitoneal liposarcomas main prognostic factor is the quality of the surgical resection. The effect of radiotherapy combined with surgery is uncertain and until now limited perhaps because of limited prescribed doses (of the order of 45Gy to 50Gy) due to high risk of organ toxicity nearby.

The helical tomotherapy is an innovative equipment radiotherapy to make conformational radiotherapy modulation intensity and is particularly suitable for irradiations precision (imaging mode associated with daily scanner) in large complex volumes. Increasing doses (increase of the prescribed dose to 54 Gy, thus potentially curative), the helical tomotherapy should allow to improve the efficacy of radiotherapy.

Retro peritoneal liposarcomas are rare (less than 15% of sarcomas) whose prognosis is locoregional. In the treatment of retroperitoneal liposarcomas main prognostic factor is the quality of the surgical resection. The effect of radiotherapy combined with surgery is uncertain and until now limited perhaps because of limited prescribed doses (of the order of 45Gy to 50Gy) due to high risk of organ toxicity nearby.

Two elements can overcome these difficulties:

* Preoperative radiotherapy made rather than Postoperatively, the tumor in place back the gastrointestinal tract and reducing toxicity,
* The contribution of conformal radiotherapy techniques with intensity modulation (IMRT). The helical tomotherapy is an innovative equipment radiotherapy to make conformational radiotherapy modulation intensity and is particularly suitable for irradiations precision (imaging mode associated with daily scanner) in large complex volumes. Increasing doses (increase of the prescribed dose to 54 Gy, thus potentially curative), the helical tomotherapy should allow to improve the efficacy of radiotherapy.

Eligibility Criteria:
Inclusion Criteria:

1. Liposarcoma histologically proven, in case of non-contributive biopsy: diagnosis radiologically validated within a multidisciplinary meeting
2. Protocol TOMOREP technically feasible,
3. Patients over 18 years
4. Considered as resectable even if multi-visceral excision is needed
5. Absence of morbidity contra-indicating surgery. The evaluation will be performed by the surgeon or the radiotherapist according to the definitions by the ASA classification.
6. Original form (as well as tumors made after first incomplete excision) and form in first relapse.
7. Life expectancy greater than 6 months
8. Patient signed informed consent,
9. Patient affiliated to a social security.

Exclusion Criteria:

1. Metastasis associated
2. Extension intraperitoneal associated, mesenteric extension
3. bilaterally
4. Against disease-indicating the need for surgery (ASA 3 and 4).
5. Contra-indication to radiotherapy (such as prior radiotherapy into the volume to treat).
6. Patient included in another clinical trial
7. Patient unable to undergo medical monitoring test for any geographical, social or psychological reasons,
8. Private patient freedom and major subject of a measure of legal protection or unable to consent.