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Adequate 3D Treatment Volume in Preoperative Radiotherapy in Extremity Soft Tissue Sarcoma. Kim BK, Chen YL, Kirsch DG, Kobayashi W, Goldberg S, Wolfgang J, Kung JH, Doppke K, Raskin KA, Springfield DS, Schwab JH, Yoon SS, Hornicek FJ, Nielson GP, DeLaney TF
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Adequate 3D Treatment Volume in Preoperative Radiotherapy in Extremity Soft Tissue Sarcoma Kim BK, Chen YL, Kirsch DG, Kobayashi W, Goldberg S, Wolfgang J, Kung JH, Doppke K, Raskin KA, Springfield DS, Schwab JH, Yoon SS, Hornicek FJ, Nielson GP, DeLaney TF Department of Radiation Oncology, Orthopedic Oncology, Surgical Oncology, Pathology, Massachusetts General Hospital, Boston, MA, USA
Background • Radiotherapy in Extremity Soft Tissue Sarcoma (STS ) • Preoperative • Postoperative • Potential Advantages of Preoperative RT • More precise definition of tumor – accurate/small field • Increase R0 resection/ possible limb preservation • Decrease the risk of tumor seeding • Complications • Increased wound complications vs. • Decreased late morbidities • Adequate 3D Treatment Volume for Preoperative RT?
Objectives • Retrospective Study • Analyze the pattern of local failure (LF). • Patients with extremity STS • Curative preoperative irradiation (XRT) • Treated with 3D XRT using CT simulation • Elucidate optimal 3D radiation field design. • Evaluate other results and prognostic factors.
Radiotherapy (Preoperative RT Volume) Gross Tumor Volume (GTV) : T1 Gd CE (+) area on MRI Clinical Target Volume (CTV) : GTV + 1-1.5 cm radial margin : GTV + 3.5 cm proximal/distal margin Planning Target Volume (PTV) : CTV + 0.5- 0.8 cm margin Dose Prescription : PTV covered by > 95 % isodoseline GTV
Survival & Local Control 93.2 % (31) 93.2% (12) 91.5% (31) 88.5% (12) Local Recurrence as First Failure (3) Local Recurrence as Cumulative Failure (5)
Margin Status & Local Failures RM Positive vs. Negative RM < 1 mm vs. > 1 mm RM < 1 mm vs. > 1 mm p = 0.0364 p = < 0.0001 p = 0.0016
Infield Failure All infield failures were located in GTV or CTV.