Neoadjuvant Chemotherapy Combined With Targeted Treatment in High-risk Retroperitoneal Sarcoma

Inclusion Criteria: * Histologically proven primary high-risk Retroperitoneal sarcoma(RPS) (Including Dedifferentiated liposarcoma (DDLPS), leiomyosarcoma(LMS), Undifferentiated pleomorphic sarcoma(UPS), Solitary fibrous tumor(SFT)). * Primary localized RPS without histories of surgical resection, chemo- or radio-therapy, targeted therapy. Patients who underwent laparotomy with biopsy only will also be considered as primary cases. * Without histories of second malignant tumors. * In DDLPS * Diagnosis should be confirmed based on MDM2(Mouse double minute 2 homolog) and CDK4(Cyclin-dependent kinase 4) expression on IHC (immunohistochemistry), while MDM2 amplification in the Fish test is highly recommended. * All grade 2-3 DDLPS can be included. * In LMS * All grades of LMS can be included. * Tumor size ≥10cm * In UPS or SFT * All grades of UPS can be included. * High-risk SFT with a score ≥6 in 'Risk stratification of SFT for development of metastasis' introduced in The 5th edition of the WHO(World Health Organization) Soft tissue sarcoma classification. * Sarcoma without protruding across the diaphragm * Possibility of R0/R1 resection evaluated through preoperative MDT(multi-disciplinary team) discussion * No multi-organ or system dysfunction/failure or patients with slight dysfunction of organ/system could be easily recovered * Tolerable of chemotherapy and surgery through MDT evaluation and tests. * American Society of Anesthesiologist (ASA) ≤3 * Fully understand the informs and consent to participate in the study. Exclusion Criteria: * Sarcoma confirmed originating from the GI tract, uterus, or urinal tract. * Patients included in the study through preoperative biopsy or MDT discussion, with WDLPS, grade 1 LPS, or other types of tumors not mentioned in the Inclusion criteria evaluating through final pathological findings. * Sarcoma protruded into the chest cavity evaluated through preoperative imaging or surgical reports. * Metastasis confirmed pathologically or highly suspicious metastatic lesions through radiological findings, PET-CT(Positron emission tomography) is highly recommended, MDT discussion and evaluation are needed. * Histories of administration of Anthracyclines, Ifosfamide, and targeted agents. * Severe contradiction to surgery and chemotherapies, including persistent myelosuppression, myocardial/cerebral/pulmonary infarction, uncontrolled cardiac arrhythmia, etc within the last 6 months * Indication of severe infection or undergoing surgeries with high-risk hemorrhages in one month. * Persistent one or more organ or system dysfunctions, could not be recovered prior to the study. * Female patients who are pregnant or breastfeeding or female and male patients of reproductive potential who are not willing to employ effective birth control methods. * Patients with psychological conditions