Liposarcoma, Myxoid

Phase I-II trial that combines trabectedin plus radiotherapy for tumor reduction response measure in four cohorts of patients: Cohort A: Patients with diagnosis of non-operable or unresectable or not oncologically recommended metastasectomy of limited to lung metastases soft tissue sarcoma. Cohort B: Patients with locally advanced resectable Myxoid Liposarcoma. Cohort C: Patients with retroperitoneal and resectable soft tissue sarcoma (liposarcoma and leiomyosarcoma). Cohort D (Phase II only): Patients with well differentiated liposarcoma and G2 dedifferentiated liposarcoma (with less than 30% dedifferentiated component). Phase I: escalating dose of 1.3 or 1.5 mg/m2. Phase I for cohort C: de-escalating dose of 1.5 or 1.3mg/m2 Radiotherapy for cohort A: 30Gy in 10 fractions (3Gy/fraction). Radiotherapy for cohort B: 45Gy in 25 fractions (1.8Gy/fraction). Radiotherapy for cohort C: 45Gy in 25 fractions (1.8Gy/fraction). Radiotherapy for cohort D: 45Gy in 25 fractions (1.8Gy/fraction). A translational substudy is developed to analyse different biomarkers predictive value. Cohorts A and B are closed to recruitment in 2023.