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UHN. In-Depth Analysis of Wound Complications F ollowing Preoperative Radiotherapy for Lower Extremity Soft Tissue Sarcoma Patients. Princess Margaret Cancer Centre. Colleen Dickie MSc, MRT(T)(MR) Assistant Professor, University of Toronto. Acknowledgements. Joanne Moseley, BMath
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UHN In-Depth Analysis of Wound Complications Following Preoperative Radiotherapy for Lower Extremity Soft Tissue Sarcoma Patients Princess Margaret Cancer Centre Colleen Dickie MSc, MRT(T)(MR) Assistant Professor, University of Toronto
Acknowledgements Joanne Moseley, BMath Anthony M. Griffin, MSc Amy Parent, MRT(T), BSc, CMD Michael B. Sharpe, PhD Peter C. Ferguson, MD, FRCSC Jay S. Wunder, MD, FRCSC Peter Chung, MD, FRCPC Charles N. Catton, MD, FRCPC Brian O’Sullivan, MD, FRCPC Princess Margaret Cancer Center
Background • Phase II preop IG-IMRT trial: • Reduced combined modality morbidities • Minimized dose to uninvolved tissues • Adult LE-STS • Reduced wound complications (WC) • from 43 % (phase III preop arm) to 30.5 % O’Sullivan et al. Cancer, 2013 May 15;119(10):1878-84.
Background • IMRT Trial priority: target coverage • Future SF spared if feasible • Overlap of flaps with PTV was a significant predictor of WC (p = 0.003) • Superficial PTVs WC • Baldini et al.: • Tumor proximity to skin surface • < 3mm predictor of WC FLAPS GTV PTV O’Sullivan et al. Cancer, 2013 May 15;119(10):1878-84. Baldini et al., Ann Surg Oncol, 2013 May;20(5):1494-9.
Objective • To retrospectively analyze all the elements of the volume of skin and subcutaneous tissues used to close the resection site (surgical flaps - SF) • Lower extremity STS • Phase II IMRT PMH trial • To determine which parameters were associated with WC
Methods / Materials • MATLAB / Pinnacle used to quantify: • Mean SF RT dose • SF Volume • Inclusion of fascia • Tumor to skin proximity • GTV and PTV FLAPS PTV FLAPS GTV PTV
Methods / Materials • MATLAB used to quantify: • SF Length • SF Width • Variable thickness across length / width of SF • SF and PTV overlap Width PTV Length
Methods / Materials • 18 of 59 (30.5%) patients developed WC in IMRT trial • 93 % primary closure (55 of 59) • 4 non primary- 1 STSG, 1 rotation flap, rotation flap and STSG • 8 patients re-planned for tumor growth • 5 developed WC (62.5 %) • Analyzed tumor growers separately
8 Growers- RT Dose Map 1st Plan • Red = prescribed dose • Minimal Overlap • Increased Overlap • Replan- Significantly greater: • SF overlap • %SF > 30 Gy • Shorter tumor to skin (2.2 mm) PTV RePlan PTV
Conclusions • WC is reduced when: • 92 % of SF is proportionally excluded from PTV • Provides volume estimate for IMRT optimization • Larger GTV / PTVs were associated with WC • Tumor growth may occur at any time during preop IMRT and may: • Increase PTV / SF overlap • Increases SF > 30 Gy • Increase WC rate
Acknowledgements Joanne Moseley, BMath Amy Parent, BSc, MRT(T) Anthony M. Griffin, MSc Michael B. Sharpe, PhD Peter C. Ferguson, MD, FRCSC Jay S. Wunder, MD, FRCSC Robert S. Bell, MD, FRCSC Peter Chung, MD, FRCPC Charles N. Catton, MD, FRCPC Brian O’Sullivan, MD, FRCPC Princess Margaret Cancer Center