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Colleen Dickie MSc, MRT(T)(MR) Assistant Professor, University of Toronto

UHN. IMRT, Designed with Evidence-Based Bone Avoidance Objectives, Reduces the risk of Bone Fracture in the management of Extremity Soft Tissue Sarcoma. Princess Margaret Cancer Center. Colleen Dickie MSc, MRT(T)(MR) Assistant Professor, University of Toronto. Acknowledgements.

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Colleen Dickie MSc, MRT(T)(MR) Assistant Professor, University of Toronto

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  1. UHN IMRT, Designed with Evidence-Based Bone Avoidance Objectives, Reduces the risk of Bone Fracture in the management of Extremity Soft Tissue Sarcoma Princess Margaret Cancer Center Colleen Dickie MSc, MRT(T)(MR) Assistant Professor, University of Toronto

  2. Acknowledgements 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

  3. Background • Severe morbidity • Review of 22 pts with internal fixation for fracture • Complications in 86% (82% non union at 12 mos) • 13 pts underwent 24 revision operations • 364 LE-STS EBRT • Females, > 55 yrs, thigh tumor location • Periosteal stripping • High (60-66 Gy – 10 %) vs. Low (50 Gy -2%) • Overall – 6.3 % crude risk • Median F/U = 58 mos Holt et al. Fractures following RT and Limb-Salvage Surgery for LE-STS: JBJS 2005 Sternheim et al. Internal fixation …high rate of failure: Bone Joint J 2013;95-B:1144–8.

  4. Background • 1989 - 2004 • Lack of 3D info • 21 pts 24 fractures: 53 control • Matched on gender, tumour size / location, age, beam arrangement, RT timing / RT dose • Fracture Risk reduced if: • V40 kept below 64% • Mean bone dose < 37 Gy • Max bone dose < 59 Gy Dickie et al. Bone Fractures following EBRT… IJROBP 2009 Nov 15;75(4):1119-24.

  5. Objective • To evaluate the potential for IMRT to reduce the risk of bone fractures: • Lower extremity soft tissue sarcoma (LE-STS) • Combined modality local treatment • Evidence based Bone Avoidance Objectives (BAO) • V40 kept below 64% • Mean bone dose < 37 Gy • Max bone dose < 59 Gy Dickie et al. Bone Fractures following EBRT… IJROBP 2009 Nov 15;75(4):1119-24.

  6. Methods / Materials • Study timeframe: 2005 – 2011 • 230 plans employed BAO from our previous study • 176 lower extremity • 54 upper extremity • Study confined to weight bearing bones to minimize reporting bias • i.e. Removed upper extremity cases (176 LE-STS) • All patients: Surgery combined with RT • 155 received preop (50 Gy) • 21 received postop (60 – 66 Gy) • 2 Gy per fraction daily

  7. Methods / Materials • 4 patients re-irradiated for in field recurrent disease • 44 Gy / 40 fractions BID 6 hours apart • 5 patients re-irradiated for recurrent disease at edge • 50 Gy in 25 fractions • We evaluated: • Mean bone dose • Max bone dose • Volume of Bone receiving > 40 Gy (V40) • Mean dose to the clinical target volume (CTV dose)

  8. Results • Target Coverage Criteria 100 % • BAO achieved: 96 % preop, 72 % postop RT plans • 4 patients experienced a bone fracture (2.2 %) • All preop 50 Gy / 25 f, 1 further 44 Gy / 40 f • 3 males, 1 female • Mean F/U= 47 mos

  9. First Fracture Case • 46 yr old Male - Crane operator • Myxoid Liposarcoma Rt Calf • Preop RT & Sx 2007 • 15 mos post Tx spiral fracture • Trauma by metal crane ring within RT volume • > 58 Gy coincided with fracture site • Treated conservatively 2008 2011 2007 High dose >58Gy • CTV mean = 50.9 Gy • Bone mean = 30.6 Gy • Bone max = 58.7 Gy • Bone V40 = 37 % • PASSED

  10. Second Fracture Case Original • UPS RT Thigh • 55 yr Male • Preop RT 2008 • Sx 2009 • In- field recurrence 2010 • Retreatment Second RT course: IMRT 44 Gy / 40 Retreat 10 cm

  11. Second Fracture Case 2012 • Proximal femur fracture 2012- fall at home • 41 mos post Tx • IM nail / Iliac crest bone graft • 6 mos no healing • Cemented proximal femur tumor prosthesis 2013 2013 • 1st Plan • CTV = 51.7 Gy • Bone mean = 35.5 Gy • Bone max = 49.8 Gy • Bone V40 = 31 % • BID plan • CTV = 40 Gy • Bone mean = 15 Gy • Bone max = 35 Gy • Bone V40 = 1 %

  12. Third Fracture Case High RT dose • 63 yr old Male • Fibrosarcoma RT Thigh • Preop RT & Sx 2007 • Disease > 60% circumferential • Fall - Fracture May 2008 • IM nail inserted GTV • FAILED • CTV mean 52.7 Gy • Bone mean 41.4 Gy • Bone max 52.9 Gy • Bone V40 75.9 %

  13. Fourth Fracture Case • UPS RT thigh • 57 yr Female • Preop RT • Disease > 60% Circumferential • 19 mos post Tx- pain • Undisplaced transverse fracture • IM nail GTV • CTV mean = 51.9 Gy • Bone mean = 26.1 Gy • Bone max = 53.7 Gy • Bone V40 = 39 % • PASSED

  14. Conclusions • Risk of fracture using BAOs is lower than previously reported • (2.2 % vs. 6.3 %) • Preferential use of preoperative RT • adverse RT morbidities • RT volumes and doses • Bone objectives are practical and beneficial • Bone sparing techniques should be employed for: • Circumferential disease • In re-irradiation settings • For women > 55 yrs

  15. Acknowledgements Anthony M. Griffin, MSc Amy Parent, BSc, MRT(T) 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

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