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course. We report on a single institution's modern NA-CRT experience in management of localized STS. Materials/Methods: Retrospective review of localized STS patients who underwent a curative course of neoadjuvant chemotherapy and radiotherapy followed by surgical resection from a single institution was performed. Cases undergoing NA-CRT for metastatic STS or with a prior history of excision were excluded from analysis. Acute radiation toxicities were quantified using the Radiation Therapy Oncology Group (RTOG) Common Terminology Criteria for Adverse Events scoring schema. Prechemoradiation and post-chemoradiation primary disease PET/CT avidity values were collected as well as final surgical resection margin status. Using the Kaplan-Meier survival analysis, 2-year local control (LC), disease-free survival (DFS), and overall survival (OS) were estimated. Results: From 2011 to 2018, 37 consecutive cases of biopsy-proven stage IA-IIIB STS to the extremities (27), pelvis (5), paraspinal region (3), adrenal gland (1), and chest wall (1) were identified. Median radiation dose delivered was 46.8 Gy (range: 16-54 Gy), and all patients underwent conventional neoadjuvant chemotherapy with the majority receiving ifosfamide (31). Following NA-CRT, mean reduction of 67% was observed in tumor PET avidity (range: 17-100%); once resected, mean tumor necrosis of 54.0% (range: 2-100%) was observed with complete response in 16.2% (nZ6) and partial response in 75.7% (nZ28). Post-treatment resection margins were negative in all patients with 21.6% having close margin of 1 mm or less and only an additional patient needing re-excision due to an initial positive margin. At median follow-up of 32.8 months (range: 3.3-88.5 months), 2-year LC was 91.7%, DFS 71.4% and OS 92.0%. Radiation was relatively well tolerated during the course of therapy: 70.3% of patients presented with grade I/II radiation dermatitis (single case of grade 3) and 21.6% with grade 1 fatigue. There were 2 cases of delay in treatment due to radiation-related grade 2 esophagitis and abscess development requiring termination of treatment after 1600cGy; 3 other cases of treatment delays were secondary to chemotherapy-related admissions. Postsurgical complications included wound infection in 10.8% (nZ4), and wound dehiscence in 8.1% (nZ3). Conclusion: Neoadjuvant sequencing of chemoradiation in STS trimodality treatment is effective and relatively well tolerated. While this singleinstitution report of NA-CRT demonstrates outstanding resection margin status and long-term local disease control, future prospective assessment of optimal sequencing and identification of reliable prognostic biomarkers and new systemic therapies would be needed for further advancements in STS management.

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Purpose/Objective(s): 3D-printing non-coplanar template (3D-PNCT) and 3D-printing coplanar template (3D-PCT) have different characteristics. It is unclear which one is more suitable to guide radioactive seeds implantation as re-irradiation for pelvic wall recurrent gynecological malignant tumor. So we compared the difference of preoperative planning parameters between the two templates, and the difference of planning parameters between preoperative planning and postoperative planning, to guide the clinical application. Materials/Methods: From January 2016 to March 2018, 33 patients with pelvic wall recurrent gynecological malignant tumor were treated with 125 I radioactive seeds implantation assisted by 3D-printing template and in our department. The age was 50 (32-71) years. The lesion volume was 40.0 (4.6-332.4) cc. All patients underwent 3D-PNCT and 3D-PCT preoperative planning. The prescription dose and seed activity of the two plannings for one patient were the same, and the D 90 of target remained similar. Ten patients assisted by 3D-PCT or the other ten patients assisted by 3D-PNCT were selected and compared with the parameters between preoperative planning and postoperative planning. The parameters included the number of needles and seeds, D 90 , D 100 , V 100 , V 150 , V 200 , external index (EI) and conformal index (CI). The comparison of the parameters was based on the Wilcoxon test. Results: In 37 cases of preoperative planning comparison, D 90 , D 100 , V 100 , EI and CI were similar between the 3D-PNCT group and 3D-PCT group (P > 0.05). The number of needles through intestine and bone in 3D-PNCT group was less than that in 3D-PCT group (0 (0-13), 0 (0-25), Z Z-2.941, P < 0.05; 0 (0-3), 0 (0-25), Z Z-2.232, P < 0.05). Both in the two groups, the number of needles through the intestine in the upper pelvic region with supine position was more than that in the middle and lower pelvic region (3D-PNCT: ZZ3.583, 3.937, P<0.01; 3D-PCT: ZZ3.625, 4.205, P<0.01). The differences of the planning parameters before and after operation were compared in patients actually used 3D-PNCT or 3D-PCT, respectively. With 3D-PCT, the seeds number of postoperative planning (48.7AE23.3) were more than that of preoperative planning (45.7AE21.5) (ZZ-2.255, P<0.05), but the dosimetric parameters of GTV showed no significant difference (P>0.05). With 3D-PNCT, there was no statistical difference between preoperative planning and postoperative planning on seed implantation and dosimetry parameters (P>0.05). Conclusion: For patients with gynecological malignancies with pelvic recurrence, both of the two preoperative planning could achieve prescription dose, but 3D-PNCT was more safe. The postoperative planning of 3D-PNCT and 3D-PNCT can achieve the dose parameters of preoperative planning in guiding 125 I radioactive seed implantation. But 3D-PNCT can more accurately meet the preoperative planning, and 3D-PCT needs to optimize the number of seeds during the operation.

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