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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Liposarcoma

Intervention / Treatment
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* Radiation: Radiotherapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Liposarcoma histologically proven, in case of non-contributive biopsy: diagnosis radiologically validated within a multidisciplinary meeting Protocol TOMOREP technically feasible, Patients over 18 years Considered as resectable even if multi-visceral excision is needed 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. Original form (as well as tumors made after first incomplete excision) and form in first relapse. Life expectancy greater than 6 months Patient signed informed consent, Patient affiliated to a social security. Exclusion Criteria: Metastasis associated Extension intraperitoneal associated, mesenteric extension bilaterally Against disease-indicating the need for surgery (ASA 3 and 4). Contra-indication to radiotherapy (such as prior radiotherapy into the volume to treat). Patient included in another clinical trial Patient unable to undergo medical monitoring test for any geographical, social or psychological reasons, Private patient freedom and major subject of a measure of legal protection or unable to consent.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Radiotherapy<br>Evaluation of the combination of radiotherapy with helical tomotherapy (54 Gy) followed by surgery in retro-peritoneal liposarcomas. | Radiation: Radiotherapy<br>* Evaluation of the efficacy of the combination with radio-surgery helical tomotherapy irradiation to a dose of radiation of 54 Gy in patients with retroperitoneal liposarcoma of operable<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cumulative Incidence Rate of Local Recurrence and Competing Risks (All Patients) | Evaluation of the efficacy of the combination with radio-surgery helical tomotherapy irradiation to a dose of radiation of 54 Gy in patients with retroperitoneal liposarcoma of operable. The effectiveness will be evaluated in terms of local recurrence-free survival 3 years. Given the data and the lack of independence between local recurrence and metastasis events, the Kaplan Meier method cannot be applied. An estimation method adapted to the presence of competing risks is necessary. Including other events (metastasis, deaths...) consist in using a competing risk analysis methodology where the specific incidence of each type of event is estimated in the presence of the other types of events. The following results represent the cumulative incidence (as a percentage) of local recurrence on the one hand and the cumulative incidence of competing risks (distant metastasis or death) on the other hand. | 3 years from start of the tomotherapy treatment | 
| Cumulative Incidence Rate of Local Recurrence and Competing Risks (Liposarcoma Well Differentiated) | Evaluation of the efficacy of the combination with radio-surgery helical tomotherapy irradiation to a dose of radiation of 54 Gy in patients with retroperitoneal liposarcoma of operable. The effectiveness will be evaluated in terms of local recurrence-free survival 3 years.Given the data and the lack of independence between local recurrence and metastasis events, the Kaplan Meier method cannot be applied. An estimation method adapted to the presence of competing risks is necessary. Including other events (metastasis, deaths...) consist in using a competing risk analysis methodology where the specific incidence of each type of event is estimated in the presence of the other types of events. The following results represent the cumulative incidence (as a percentage) of local recurrence on the one hand and the cumulative incidence of competing risks (distant metastasis or death) on the other hand. | 3 years from start of the tomotherapy treatment | 
| Cumulative Incidence Rate of Local Recurrence and Competing Risks (Liposarcoma Dedifferentiated or Pleomorphic) | Evaluation of the efficacy of the combination with radio-surgery helical tomotherapy irradiation to a dose of radiation of 54 Gy in patients with retroperitoneal liposarcoma of operable. The effectiveness will be evaluated in terms of local recurrence-free survival 3 years.Given the data and the lack of independence between local recurrence and metastasis events, the Kaplan Meier method cannot be applied. An estimation method adapted to the presence of competing risks is necessary. Including other events (metastasis, deaths...) consist in using a competing risk analysis methodology where the specific incidence of each type of event is estimated in the presence of the other types of events. The following results represent the cumulative incidence (as a percentage) of local recurrence on the one hand and the cumulative incidence of competing risks (distant metastasis or death) on the other hand. | 3 years from start of the tomotherapy treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With Disease-Free Survival (All Patients) | Evaluation of the efficacy of the combination with radio-surgery helical tomotherapy irradiation to a dose of radiation of 54 Gy in patients with retroperitoneal liposarcoma of operable. The effectiveness will be evaluated in terms of disease free survival rate at 3 years, with the kaplan-meier method. The disease-free survival time is calculated between the date of the start of the tomotherapy treatment and the date of death, distant metastasis or local recurrence (events), whichever occur first, or the date of last news (censorship). | 3 years from start of the tomotherapy treatment | 
| Percentage of Participants With Disease-Free Survival (Liposarcoma Well Differentiated) | Evaluation of the efficacy of the combination with radio-surgery helical tomotherapy irradiation to a dose of radiation of 54 Gy in patients with retroperitoneal liposarcoma of operable. The effectiveness will be evaluated in terms of disease free survival rate at 3 years, with the kaplan-meier method. The disease-free survival time is calculated between the date of the start of the tomotherapy treatment and the date of death, distant metastasis or local recurrence (events), whichever occur first, or the date of last news (censorship). | 3 years from start of the tomotherapy treatment | 
| Percentage of Participants With Disease-Free Survival (Liposarcoma Dedifferentiated or Pleomorphic) | Evaluation of the efficacy of the combination with radio-surgery helical tomotherapy irradiation to a dose of radiation of 54 Gy in patients with retroperitoneal liposarcoma of operable. The effectiveness will be evaluated in terms of disease free survival rate at 3 years, with the kaplan-meier method. The disease-free survival time is calculated between the date of the start of the tomotherapy treatment and the date of death, distant metastasis or local recurrence (events), whichever occur first, or the date of last news (censorship). | 3 years from start of the tomotherapy treatment | 
| Percentage of Participants With Overall Survival (All Patients) | Evaluation of the efficacy of the combination with radio-surgery helical tomotherapy irradiation to a dose of radiation of 54 Gy in patients with retroperitoneal liposarcoma of operable. The effectiveness will be evaluated in terms of overall survival rate at 1, 3 and 5 years, with the kaplan-meier method. The overall survival time is calculated between the date of the start of the tomotherapy treatment and the date of death (event), or the date of last news (censorship). | 1 year, 3 years and 5 years from start of the tomotherapy treatment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Retroperitoneal liposarcoma operable