Radiotherapy And Sarcomas


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  • Sarcomas are rare malignant tumours that arise from mesenchymal tissue at any body site. Represents <15 of new malignant tumours diasgnosed. Heterogenous group of tumours including more than 40 subtypes. The tumours appear to arise from malignant precursor cells which can differentiate along one or several linaeges syuch as muscle, adipose, fibrous, cartilage or vascular tissue. Subtypes differ in clinical behaviour and aggressiveness, dissemination pattern and sensitivity.
  • Except for small peak in incidence in early childhood (accounted for primarily by embryonal RMS) STS as a whole increases in frequency with advancing age and is most common in patients over the age of 50. Anatomic distribution of soft tissue sarcomas in 4508 adults reviewed by American Colege of Surgery was as follows
  • RCT Phase III – Yang et al, JCO, 1998
  • Study was not powered to look at local control, PFS or OS, these were all secondary endpoints
  • If you had a small lesion that had been widely excised you may not give radiotherapy but this decision needs to on individual basis
  • In Canada all patients receive pre-op radiotherapy, UK standard treatment is post op If we give it pre op they receive 50gy then have 4-6 weeks gap prior to surgery and then recive 16Gy boost if positive margins
  • Hard when dry and placed in water to soften Optimum position - ? Other leg abducted, flexed out of way?
  • Allowing 5-10 mm for set-up error Vortex study suggest 5 mm enough for immobilised patients and 10mm for non-immobilised patients
  • Lymphoedema is common even with sparing a corridor so the more limb that can be spared the less risk Caused by fibrosis of skin and muscle
  • Smaller margins in Craniocaudal direction, set-up variability will become increasingly important 0.5 To assess if a reduced volume of post-operative radiotherapy increases limb function without compromising local control Suggests that majority of local recurrences occur within the high dose volume
  • To ensure that on average 99% target volume receives 95% of prescribed dose
  • On anterior images
  • Informed consent Follow up on treatment Usually seen week 4 in OPD, weekly by nurses in floor clinic
  • Tumour extended distally so leg was externally rotated for treatment and planning
  • 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