Preoperative Moderately Fractionated IMRT for Locally Extremity or Trunk Sarcoma (SPARE-03)

Inclusion Criteria: * Age older than 18 years. * Histology proven soft tissue sarcoma of truncal or extremity, deemed appropriate for preoperative radiotherapy and conservative surgery by multidisciplinary discussion. * ECOG 0-3 * Histology reviewed by reference pathologist * Lesion can be assessed * Can tolerate radiotherapy and Fluzoparib (Fluzoparib group) * Agree contraception. * Informed consent: All patients must sign a document of informed consent indicating their understanding of the investigational nature and risks of the study before any protocol related studies are performed Exclusion Criteria: * No gross tumor post-resection in other center. * Contraindications to Fluzoparib, including allergic to Fluzoparib, active bleeding, ulcer, enteric perforation, enteric obstruction, uncontrolled hypertension, Grade 3 to 4 cardiac insufficiency (per NYHA criteria), and severe hepatic or renal insufficiency (Grade 4), etc. * Dermatofibrosarcoma protuberans(DFSP), Desmoids, etc. * Benign histology * Secondary cancer within 5 years (except cervical carcinoma in situ or early-stage skin basal cell carcinoma) * STS can be cured by extensive operation alone. * Previous irradiation to the same area * radiological evidence of distant metastases * Other contraindications, can't tolerate operation or other treatment needed in this study.