Author of

• 20130

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  MA 09 - The Current Status of Radiation Oncology (ID 666)

  • Event: WCLC 2017
  • Type: Mini Oral
  • Track: Locally Advanced NSCLC
  • Presentations: 1
  • Moderators:Tomoki Kimura, Yong Chan Ahn
  • Coordinates: 10/17/2017, 11:00 - 12:30, Room 316

  • 23595

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    MA 09.09 - Isotoxic Dose-Escalated Radiotherapy (RT) in Non-Small Cell Lung Cancer (NSCLC) with Deep Inspiration Breath Hold (DIBH) (ID 10052)

    12:00 - 12:05  |  Author(s): M. Ahmed
    • Abstract
    • Presentation
    • Slides

    Background:
    With interest in the use of isotoxic dose-escalated RT in treatment of inoperable NSCLC, this study investigated the impact of DIBH using the Active Breathing Coordinator™ (ABC- Elekta, Stockholm, Sweden) device on isotoxic dose escalation potential.
    
    Method:
    Following informed consent, a four-dimensional (4D) planning CT scan and a DIBH scan using the ABC device were acquired in patients sequentially in the same session. A motion-encompassing target volume on the 4D scan and a motion-managed target volume on the DIBH scan were created. The RayStation radiotherapy treatment planning system (research version 5.99.0.16) was used to generate two corresponding volumetric modulated arc therapy (VMAT) plans for each patient, following the guidelines of the isotoxic IMRT trial (NCT01836692). The target dose was escalated up to a maximum of 79.2 Gy in 44 twice daily fractions and plans optimised to minimise dose to normal tissues. Potential to escalate target dose and differences in dose-volume metrics between the plans were compared using the Wilcoxon signed-rank test.
    
    Result:
    21 patients were included. The mean total lung volume was significantly higher with DIBH compared to 4D scans with an increase of 44.7 % ± 17.4 % (mean ± standard deviation), p < 0.001). In 20/21 patients, the maximum target dose of 79.2 Gy was achievable in both plans, however in one patient 61.2 Gy was achieved with 4D compared to 75.6 Gy with DIBH planning. In the 20 patients achieving equivalent target dose-escalation, the mean lung dose was 17.0 Gy (± 0.3Gy ) with 4D versus 14.6 Gy (± 0.3 Gy) with DIBH (p < 0.001). There was a significant mean reduction in heart dose between the DIBH compared to 4D plans of 0.3 Gy (± 0.2 Gy, p< 0.001) and significant reductions in heart D100 %, D66 % and D33 %(p < 0.01). Mediastinal envelope and oesophageal doses were similar using both techniques.
    
    Conclusion:
    The use of DIBH compared to 4D planning aids lung and cardiac sparing in isotoxic dose escalated RT and for a small number of patients may allow an increase in target dose. Particularly given the interaction between lung and cardiac toxicity in locally advanced NSCLC treated with radical RT, use of DIBH for treatment may lead to a reduction in toxicity compared to a 4D approach. In acknowledgement of the use of a mid-ventilation technique in some institutions, comparison with this method is planned.
    
    

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