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Ryan M. Lanning , Sean L. Berry, Michael R. Folkert , and Kaled M. Alektiar

Quantitative Dosimetric Analysis Of Patterns Of Local Relapse After IMRT For Primary Extremity Soft Tissue Sarcomas. Ryan M. Lanning , Sean L. Berry, Michael R. Folkert , and Kaled M. Alektiar Dept. of Radiation Oncology and Medical Physics Memorial Sloan-Kettering Cancer Center.

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Ryan M. Lanning , Sean L. Berry, Michael R. Folkert , and Kaled M. Alektiar

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  1. Quantitative Dosimetric Analysis Of Patterns Of Local Relapse After IMRT For Primary Extremity Soft Tissue Sarcomas Ryan M. Lanning, Sean L. Berry, Michael R. Folkert, and Kaled M. Alektiar Dept. of Radiation Oncology and Medical Physics Memorial Sloan-Kettering Cancer Center

  2. Disclosures • We have no conflicts of interest to disclose.

  3. Characterizing Local Recurrence Marginal Scar Central RT Field Distant

  4. Objectives • Characterize local recurrence of extremity STS treated with adjuvant IMRT based on dose received to the recurrence volume. • Determine any patient, tumor, or treatment characteristics that may predict local recurrence.

  5. Soft Tissue Sarcoma Study Population

  6. Tumor and Treatment Characteristics

  7. Original RT Fields and LR Patterns

  8. Recurrence Based on Dose Distribution Recurrence CTV PTV

  9. Dosimetric Characterization of Recurrence V95 Volume (%) Dose (% Prescription) * : Milano MT et al. IJROBP 2010

  10. Outcomes Median Follow-up = 42 months

  11. Predictors of Local Recurrence Site: p = 0.75 Grade: p = 0.95 Depth: p = 0.24 Chemo: p = 0.66

  12. Conclusions • Dosimetric analysis provides a quantitative tool for characterizing local recurrence • Traditional predictors of local recurrence in STS appear to exert less influence in the setting of IMRT Treatment Tumor Biology

  13. Acknowledgements • My collaborators: Dr. Sean Berry and Dr. Michael Folkert • My mentor: Dr. KaledAlektiar • CTOS selection committee, Committee chairs, and our discussant

  14. Room for Improvement?

  15. Recurrence Characteristics S = Surgery C = Chemotherapy R = EBRT B = Brachytherapy

  16. Volume Expansion: Pre-op IMRT CTV: GTV + 1-1.5 cm in radial axis CTV: GTV + 4 cm in long axis PTV: CTV plus 1 cm margin in all directions

  17. Volume Expansion: Postop IMRT CTV: Tumor bed + 1-1.5 cm in radial axis CTV : Tumor bed +4 cm in long axis PTV: CTV plus 1 cm margin in all directions

  18. Local Recurrence: EBRT vs IMRT • Competing risks, cumulative incidence, Gray’s test and Fine and Gray regression were used to estimate 5-y local recurrence: • IMRT:7.6% (95% CI 3.4-11.8%) • Conventional EBRT: 15% (95% CI 9.2-20.9%) P = 0.049 Courtesy of MR Folkert

  19. Discussion points – Basis of Improved Outcome? • Improved conformality and homogeneity of dose may be the basis of improved local control. Courtesy of MR Folkert Swanson EL et al, Int J Radiation Oncology Biol Phys. 2012 83(5):1549-57. Stewart AJ et al, RadiotherOncol. 2009 Oct;93(1):125-30. Griffin AM et al, Int J RadiatOncolBiol Phys. 2007 Mar 1;67(3):847-56.

  20. Predictors of Local Recurrence Depth: p = 0.24 Chemo: p = 0.66

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