Author of

• 25954

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  P2.17 - Treatment of Locoregional Disease - NSCLC (Not CME Accredited Session) (ID 966)

  • Event: WCLC 2018
  • Type: Poster Viewing in the Exhibit Hall
  • Track:
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall

  • 27317

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    P2.17-06 - Functional Lung Imaging in Radiotherapy for Lung Cancer: A Systematic Review and Meta-Analysis (ID 11149)

    16:45 - 18:00  |  Author(s): Michael S Hofman
    • Abstract
    • Slides

    Background
    

    Advanced imaging techniques allow functional lung information to be derived and integrated into treatment planning. A prospectively registered systematic review was conducted to: i) assess pre-treatment functional dose metrics as predictors of radiation pneumonitis, ii) evaluate dose response relationships, iii) assess potential utility in radiotherapy treatment planning.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    A structured search was performed for publications including key words for functional imaging, lung cancer and radiotherapy following PRISMA guidelines. Publications were required to have majority of the patients with lung cancer, age over 18, published in a peer reviewed journal and describe a radiotherapy application. Review articles and technical descriptions of functional imaging techniques were excluded. Studies with less than 10 patients were excluded from the meta-analysis. Literature searches were conducted in October 2017 in 3 electronic databases: Ovid Medline, Ovid EMBASE and Cochrane CENTRAL via the Wiley platform. The date of coverage was restricted to 1990 onwards and searches were limited to articles in English only.

    4c3880bb027f159e801041b1021e88e8 Result
    

    814 articles were screened against the review criteria: 158 publications were selected for full text review, of these 114 met criteria. The most commonly used investigations were SPECT (64 publications), CT (44), MRI (12) and PET (5).

    Ten publications evaluated pre-treatment functional lung dose-metrics as a predictor of radiation pneumonitis, 7 of these found that functional V20 and/or functional MLD correlate with the risk of clinically significant radiation pneumonitis. 6 studies comparing differences between functional and anatomical dose metrics at predicting radiation pneumonitis found higher predictive values using functional dose metrics.

    Twenty one studies described a dose-response relationship on post-treatment functional lung imaging. Dose-response curves were provided in 5 papers with a majority of these curves exhibiting a sigmoid shape and two curves showing a threshold dose between of 40-50Gy. 9 studies described the phenomenon of reperfusion post radiotherapy.

    Nineteen planning studies demonstrated the ability of functional lung optimized planning techniques to spare regions of functional lung.

    Meta-analysis of these studies found that mean (95% CI) functional volume receiving 20Gy was reduced by 4.19% [2.34; 6.04] and mean lung dose by 2.18Gy [1.09; 3.26] when plans were optimized to spare functional lung.

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    There is significant heterogeneity identified in imaging techniques, definitions of functional lung and in the reporting of available studies. Whilst the current literature suggests possible correlations with dose to functional lung and clinical toxicity and the utility of functionally adapted radiotherapy delivery, there is a need for prospective interventional trials with clinical endpoints as outcome measures.

    6f8b794f3246b0c1e1780bb4d4d5dc53

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