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Nicholas Hardcastle



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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
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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): Nicholas Hardcastle

      • 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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    P3.08 - Oligometastatic NSCLC (Not CME Accredited Session) (ID 974)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall
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      P3.08-17 - Paediatric Motion Management Solutions for Particle Therapy Based Thoracic Stereotactic Ablative Body Radiotherapy (SABR) (ID 12856)

      12:00 - 13:30  |  Author(s): Nicholas Hardcastle

      • Abstract
      • Slides

      Background

      We have recently developed a paediatric protocol for the treatment of pulmonary metastases using Stereotactic Ablative Body Radiotherapy (SABR). In thoracic SABR the treatment is commonly planned to the internal target volume, which encompasses the gross tumour and excursion of the tumour in space.Particle therapy has been shown to be beneficial in paediatric patients, but unfortunately, most systems do not have respiratory motion management thereby limiting their utility in thoracic patients. We model the implementation of strategies such as ventilation using CPAP or deep inspiration breath hold (DIBH).The purpose of this study was to establish the benefit seen in a prospectively evaluated paediatric cohort to inform clinical trials.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Patients

      Two patients with a single lesion, and one patient with 3 lesions were volumed. Average age was 12 years (range 6 to 16), prescription dose was 24Gy in one fraction. Clinical volumes were based on the Maximum Intenstiy Projection (MIP) and this ITV covered all motion seen on 10 phases of respiratory binning. The test dataset was contoured on the maximum exhale dataset (ME), as this was felt to be the most stable respiratory phase. 5 mm was added to create the PTV. Dynamic conformal arc (DCAT) was used for planning using 6MV photons with 3 to 5 arcs.

      4c3880bb027f159e801041b1021e88e8 Result

      Reduction in radiotherapy target volumes:Exhale scans resulted in a reduction in the radiotherapy target volumes for all lesions with the average± standard deviation of the PTV being 3.85± 2.52 cc and 2.51± 1.35cc for MIP vs. ME scans respectively.

      Reduction in dose to lung and heart: V5Gy (%) was also reduced from a mean of 6.0±4.10 vs. 4.63 ±2.73 % for MIP vs. ME scans respectively. For the 2 patients with lesions near the heart the mean heart dose was also reduced from 2.35±0.78 Gy vs. 1.8± 0.28 Gy for the MIP vs. ME scans respectively.

      The maximum reduction was seen for patient 3, PTV was reduced from 8.2 to 4.9 cc, the V5Gy(%) was reduced from 10 to 4.9% and the mean heart dose dropped from 2.9 to 2.0 Gy.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Respiratory motion management strategies such as DIBH and CPAP may be suitable for paediatric patients who are old enough to comply with these strategies, and who do not require general anaesthesia. As in adult patients, the implementation of these strategies reduces the radiotherapy target volume, and results in lower doses to critical normal organs such as the lung and heart.

      6f8b794f3246b0c1e1780bb4d4d5dc53

      Only Active Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login or select "Add to Cart" and proceed to checkout.