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Marianne C Aznar



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    MA05 - Improving Outcomes in Locoregional NSCLC II (ID 901)

    • Event: WCLC 2018
    • Type: Mini Oral Abstract Session
    • Track: Treatment of Locoregional Disease - NSCLC
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 13:30 - 15:00, Room 105
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      MA05.06 - Locally Advanced Lung Cancer Radiotherapy in Deep Inspiration Breath Hold: Dosimetric Benefits from a Prospective Trial (ID 12465)

      14:05 - 14:10  |  Author(s): Marianne C Aznar

      • Abstract
      • Presentation
      • Slides

      Background

      Radiotherapy for locally advanced non-small cell lung (NSCLC) cancer is often complicated by treatment-related toxicity. A toxicity-reducing technique is deep inspiration breath hold (DIBH), where the lungs inflate and the heart is pushed downwards. DIBH is widely applied in breast radiotherapy, but only sporadically in NSCLC. We initiated the INHALE trial, investigating compliance and benefits of DIBH for NSCLC at a single academic institution.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Patients referred for definitive radiotherapy of locally advanced NSCLC (66Gy/33 fractions) were included from May 2015-Dec 2017. All patients underwent respiratory coaching for voluntary visually guided DIBH and were imaged with PET/CT, 4D-CT and DIBH-CT. Target volumes were defined according to national guidelines. PTV margins were patient- and modality-specific. For all patients, FB and DIBH plans were made with volumetric modulated arc therapy, with equal PTV coverage. The plan with the lowest lung and/or heart dose was chosen for treatment. Normal tissue complication probability for pneumonitis was calculated retrospectively based on a logistic dose response model.

      4c3880bb027f159e801041b1021e88e8 Result

      The treatment intent was maintained in 69 of included 88 patients (2 were downstaged, 12 upstaged, 2 withdrew consent, other causes in 3). 62/69 were DIBH compliant and in 61 patients a FB and a DIBH plan were made (in one patient, 4DCT image quality was not sufficient). In 54/61 patients, the DIBH plan was chosen for treatment. 3/54 patients lost DIBH compliance within the first few fractions.

      All data is presented as median (range), with p<0.001 (Wilcoxon signed rank). Lung volume increased in DIBH by 55% (20-168%). Compared to FB, DIBH reduced mean lung dose from 14.4Gy (1.2-25.3Gy) to 11.8Gy (1.0-20.4Gy), and lung V20 from 23.7% (1.5-47.8%) to 20.8% (1.2-39.7%). Reduced lung dose translated to reduced pneumonitis risk: from 8.6% (2.3-23.3%) to 6.5% (2.2-14.4%). Lung dose constraints were violated in 5/62 patients in FB and 1/62 patients in DIBH.

      Mean heart dose was reduced from 3.6Gy (0.1-25.8Gy) in FB to 2.4Gy (0.1-25.3Gy) in DIBH. DIBH reduced mean heart dose in 44/61 patients. The differences between FB and DIBH varied between – 6.6Gy and 8.9Gy, stressing the influence of tumour location on the potential of reducing heart dose with DIBH.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Benefits of changed anatomy with DIBH were reduced dose to lungs and, for most patients, to the heart. Curative treatment intent could be maintained in more patients. Risk of developing radiation pneumonitis was reduced. Continuous follow up of INHALE patients will reveal how the reduced risk is manifested clinically.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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    P2.16 - Treatment of Early Stage/Localized Disease (Not CME Accredited Session) (ID 965)

    • 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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      P2.16-08 - Influence of Tumour Location and Histological Sub-Type of Non-Small Cell Lung Cancer on Patient Survival (ID 13836)

      16:45 - 18:00  |  Author(s): Marianne C Aznar

      • Abstract
      • Slides

      Background

      In non-small cell lung cancer (NSCLC), adenocarcinomas tend to arise peripherally and squamous cell carcinomas (SCC) centrally. Tumour location is known to impact patient survival: in previous work, we showed that right-sided tumours show worse survival, n=1101; HR=1.25, p<0.01. In this study we extended the laterality analysis by including histological sub-type and explore its correlation with overall survival.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      529 unselected NSCLC patients (treated with 55Gy/20fr), with confirmed adenocarcinoma or SCC, were included. All patients were spatially normalised using non-rigid registration to a reference anatomy, allowing tumour probability maps to be created from the outlined tumours. A Kolmogorov-Smirnov test assessed differences in distributions.

      Kaplan-Meier curves, grouped by histological sub-type, were plotted. Tumour volumes were extracted for all patients and included in a multi-variate analysis including N-stage, performance status, gender and median dose to left and right lungs, encoding laterality.

      4c3880bb027f159e801041b1021e88e8 Result

      326 adenocarcinomas and 203 SCC were found. Tumour probability maps show a clear separation in tumour locations between the sub-types (Fig.1a, p<0.001) and a general location of SCC tumours along the major airways. Tumour volumes were significantly different (SCC larger, median 56cm3 versus 14cm3, p<0.001, Fig.1b). Histology also influences nodal involvement, 20% adenocarcinomas versus 80% SCC are N+. Location and volume impacts on normal tissue doses, mean lung and heart doses: 8.8Gy and 4.9Gy for adenocarcinomas, 15.6Gy and 18.8Gy for SCC.

      SCC patients showed worse survival (median 12 versus 21 months, Fig.1c). Multivariate analysis shows right lung mean doses significantly correlate with survival for adenocarcinomas, p=0.04, but not for SCC, p=0.2, indicating the spatial location of the tumour may have an interaction with our previously described laterality effect.

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      8eea62084ca7e541d918e823422bd82e Conclusion

      Differences in the spatial locations and volumes of histological sub-types influence normal tissue doses including the effect of tumour laterality on survival. Further work will explore possible mechanisms, including ventilation/perfusion variation in the lungs.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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