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Radiotherapy And Sarcomas


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Radiotherapy And Sarcomas

  1. 1. Radiotherapy and Sarcomas Wendy Ella University College London Hospitals NHS Foundation Trust
  2. 2. Introduction <ul><li>Rare malignant tumours arising from mesenchymal tissue </li></ul><ul><li><1% malignant tumours </li></ul><ul><li>78% originate from soft tissue, remainder from bone </li></ul><ul><li>Diverse group </li></ul>
  3. 3. Heterogenous group of tumours <ul><li>Malignant Fibrous histiocytoma 28% </li></ul><ul><li>Liposarcoma 15% </li></ul><ul><li>Leiomyosarcoma 12% </li></ul><ul><li>Synovial sarcoma 10% </li></ul><ul><li>MPNST 5% </li></ul><ul><li>Rhabdomyosarcoma 5% </li></ul><ul><li>Fibrosarcoma <5 </li></ul><ul><li>Ewings sarcoma </li></ul><ul><li>Angiosarcoma </li></ul><ul><li>Osteosarcoma </li></ul><ul><li>Clear cell sarcoma </li></ul><ul><li>Alveolar soft part sarcoma </li></ul><ul><li>Hamangiopericytoma </li></ul><ul><li>Chondrosarcoma </li></ul>
  4. 4. Introduction <ul><li>Increasing frequency with age </li></ul><ul><li>Most commonly arising in the limbs </li></ul><ul><ul><li>Extremities 50% </li></ul></ul><ul><ul><li>Trunk and retroperitoneal space 40% </li></ul></ul><ul><ul><li>Head and neck region 10% </li></ul></ul>
  5. 5. Heterogenous group of tumours
  6. 6. Heterogenous group of tumours
  7. 7. Heterogenous group of tumours
  8. 8. Heterogenous group of tumours
  9. 9. Principles of management: soft tissue sarcomas Surgery +/- Radiotherapy +/- Chemotherapy
  10. 10. Radiotherapy for soft tissue sarcoma <ul><li>Radiotherapy – role optimise local control </li></ul><ul><li>Local control rates for combination of surgery + radiotherapy similar to amputation without affecting patient survival (Potter et al; 1986). </li></ul><ul><li>Yang et al , J Clin Oncol, 1998, looked at high grade extremity lesions: Surgery vs Surgery + EBRT (63Gy in 1.8Gy), - increased local control from 70% to 99%, No difference in OS. </li></ul><ul><li>Summary : Post operative radiotherapy is highly effective in preventing local recurrence. </li></ul>
  11. 11. Pre- or Post-Op Radiotherapy ? <ul><li>O’Sullivan et al; Five year results of randomised phase III trial of pre-op vs. post-op radiotherapy in extremity STS; JCO 2004 </li></ul><ul><li>190 patients (94 pre-op/96 post-op) 5 year local control 93% v 92%, metastatic relapse free 67% v 69%, recurrence free survival; 58% v 59%, overall survival 73% v 67% </li></ul><ul><li>Pre-op and post-op radiotherapy equally effective, normal tissue complication rate varies for both - therefore need to take in to account anatomical site </li></ul>
  12. 12. Indications for Post Operative Radiotherapy; <ul><li>Consider for all high grade sarcomas . </li></ul><ul><li>Consider for low-intermediate grade with marginal excision/positive margins if further surgery not possible </li></ul><ul><li>Following removal of recurrent tumour </li></ul>
  13. 13. Indications for pre-operative radiotherapy <ul><li>If tumour adjacent to or involving critical structures. </li></ul><ul><li>Likely difficult resection. </li></ul><ul><li>Tumour initially inoperable at diagnosis </li></ul>
  14. 14. Planning post-operative radiotherapy <ul><li>Immobilisation </li></ul><ul><li>Definition of target volume </li></ul><ul><li>Phase I & II </li></ul><ul><li>Field arrangements </li></ul><ul><li>Implementation of plan </li></ul>
  15. 15. Immobilisation <ul><li>Impression of limb with patient in the optimum treatment position -sheet of thermoplastic (Orfit) moulded around limb – clipped onto baseboard </li></ul><ul><li>Immobilise limb </li></ul><ul><li>Same position every day </li></ul><ul><li>Reduce marks being drawn on skin </li></ul>
  16. 16. Immobilisation: Lower limb
  17. 17. Immobilisation: Upper limb
  18. 18. Phase I Volume definition <ul><li>GTV reconstructed from pre-op imaging. </li></ul><ul><li>Consider compartment at risk of microscopic spread. Should include biopsy site and scar </li></ul><ul><li>CTV (length) = GTV + 4-9cm (usually ~5cm) </li></ul><ul><li>PTV = CTV + 5-10mm (depending on departmental set up) or 1 cm beyond scar </li></ul><ul><li>Trans-axial CTV - treat width of compartment or </li></ul><ul><li>GTV + 2-3cm </li></ul>
  19. 19. Phase II Volume definition <ul><li>Length </li></ul><ul><li>PTV = GTV +2-3cm </li></ul><ul><li>Width </li></ul><ul><li>PTV is usually the same as phase I in axial plane </li></ul>
  20. 20. Sparing a “corridor ” <ul><li>Leaving an area of normal tissue within the circumference of the limb can reduce risk of lymphoedema </li></ul>
  21. 21. Vortex <ul><li>CTV1 = axial 2cm or fascia </li></ul><ul><li>Longitudinal 2cm </li></ul><ul><li>CTV2 = axial 2cm or fascia </li></ul><ul><li>Longitudinally 2cm </li></ul><ul><li>CTV- PTV = 5mm </li></ul>
  22. 25. Margin calculation <ul><li>Van Herk, Seminars in Radiation Oncology, 14, 2004, 52-64 </li></ul><ul><li>Margin = (2.5 X SD of group systematic error) + (0.7 X SD of random error) </li></ul>
  23. 26. Systematic/Random errors Margin = (2.5 X SD of group systematic error) + (0.7 X SD of random error) - Van Herk, 2004 4.4 mm +/- 0.8mm 0.3 mm +/- 1.5 SD A–P on Lat 5.3 mm +/- 1.7mm -0.2 mm +/- 1.7 SD S-I on AP 4.3 mm +/- 1.1mm 0.2 mm +/- 1.4 SD L-R on AP Margins calculated Group SD of random error Group systematic error
  24. 27. Implementation of Plan <ul><li>6MV photons </li></ul><ul><li>Prescribed to 100% </li></ul><ul><li>Given isocentrically treating all fields daily </li></ul><ul><li>Limbs 2 phase technique; </li></ul><ul><li> phase I 50Gy in 25# over 5 weeks </li></ul><ul><li>phase II 10 -16Gy in 5# over 1 week </li></ul><ul><li>60Gy is standard post op dose, 66Gy if positive margin </li></ul>
  25. 28. MRI Scan
  26. 29. Planning
  27. 30. Planning
  28. 31. Radiotherapy for soft tissue sarcoma <ul><li>Complex radiotherapy </li></ul><ul><li>Highly individualised </li></ul><ul><li>Requires good anatomical knowledge </li></ul>
  29. 32. Questions? University College London Hospitals NHS Foundation Trust