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