Virtual Library

Start Your Search

Eliana Vasquez Osorio



Author of

  • +

    OA01 - Improving Outcomes in Locoregional NSCLC I (ID 892)

    • Event: WCLC 2018
    • Type: Oral Abstract Session
    • Track: Treatment of Locoregional Disease - NSCLC
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 10:30 - 12:00, Room 107
    • +

      OA01.03 - Interaction Between Dose and Calcifications Is a Predictor for Overall Survival in Lung Cancer Patients Receiving Radiotherapy (ID 13920)

      10:50 - 11:00  |  Author(s): Eliana Vasquez Osorio

      • Abstract
      • Presentation
      • Slides

      Background

      Recently, incidental dose to the heart was found to be predictive for overall survival in lung cancer patients receiving radiotherapy [McWilliam et al EJC 2017, Johnson et al Radiother Oncol 2018]. These patients often present with multiple comorbidities that should be incorporated in survival analysis. However, such data is often missing. We investigated whether calcifications, identified on the radiotherapy planning CT, can be used as a surrogate for cardiac health. In particular, we investigated the interaction between calcifications, dose and survival.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Data from 814 unselected non-small cell lung cancer patients was used, all treated with 55Gy in 20 fractions. Methodology was developed to automatically segment calcifications within the heart, the aortic arch and their surroundings. The 3D planning CT scans, and the associated lung and spinal cord delineations were processed using well-established image processing algorithms, e.g., convex hull, thresholding, morphological operations, connected pixel analysis and flood filling to detect calcifications. Moreover, shape analysis was included to enhance regions that presented tubular or plate-like appearance. The detection algorithm was validated in a small subset of 10 patients, and this group was used to determine the success and error rate of the automatic segmentation. Finally, a Cox-proportional hazards multivariate analysis was performed for overall survival of all patients accounting for tumour size, total calcification volume, mean dose across all identified calcifications, and interaction between calcification volume and dose.

      4c3880bb027f159e801041b1021e88e8 Result

      The success rate of the algorithm for identifying calcifications was 81.8%, its error rate was 8.8%. The multivariate survival analysis identified tumour size (continuous, p<<0.0001) and the interaction of calcification volume and their mean dose (continuous, p=0.029) as significant. Calcification volume (p=0.57) or mean calcification radiation dose alone (p=0.269) were not found to be significant.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Multivariate analysis shows a significant interaction between volume of the identified calcifications and their mean radiotherapy dose predicting survival. Further improvements to identify calcifications in the descending thoracic aorta and validation of our methodology are required. Further work linking our results with the established Agatston or Coronary Artery Calcium score is in progress.

      * EVO-FB share first authorship

      6f8b794f3246b0c1e1780bb4d4d5dc53

      Only 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, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.

      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.

  • +

    P1.17 - Treatment of Locoregional Disease - NSCLC (Not CME Accredited Session) (ID 949)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
    • +

      P1.17-01 - Robustness of an Image-Based Data Mining Approach in Lung Cancer Patients (ID 13384)

      16:45 - 18:00  |  Author(s): Eliana Vasquez Osorio

      • Abstract

      Background

      Image-based data mining (IBDM) enables exploring the correlation of dose distributions and outcomes in large cohorts of patients without the requirement of additional contouring. IBDM has recently identified the dose to the base of the heart as an important predictor for overall survival (OS) in lung cancer patients receiving radiotherapy [McWilliam et al EJC 2017]. IBDM relies on non-rigid registration to set inter-patient dosimetric data into a common reference anatomy or reference patient. Here, we investigated the uncertainties associated with the choice of reference patient, and their influence on the correlation between incidental dose to the base of the heart and OS.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      In previous work, 1101 NSCLC patients (55Gy / 20 fractions) were randomly selected, and their planning CT images non-rigidly registered to a reference patient CT scan using NiftyReg (http://cmictig.cs.ucl.ac.uk/wiki/) as part of IBDM process. In this work, 5 additional patients with small cell lung cancer (i.e. without a large tumour burden) were used as “reference patients” and the IBDM analysis in the whole cohort was repeated for each reference patient. Permutation testing with 100 iterations was applied to assess statistical significance.

      4c3880bb027f159e801041b1021e88e8 Result

      slide1.jpg

      Figure 1 shows the regions of highly significant correlation between dose and OS for each reference patient. In spite of large variations in anatomy between the reference patients, each analysis identified similar anatomical regions as significantly associated with OS (t>5). Moreover, permutation testing was consistent with the original findings.

      8eea62084ca7e541d918e823422bd82e Conclusion

      IBDM is a robust approach and, in this analysis, does not appear to be sensitive to the choice of reference patient for the investigated dose-effect correlation. Prospective studies are necessary to confirm the correlation between dose to the base of the heart and OS in NSCLC patients. Methodological studies are needed to determine the level of effect strength and region size that this general technique can identify.

      6f8b794f3246b0c1e1780bb4d4d5dc53

  • +

    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
    • +

      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): Eliana Vasquez Osorio

      • 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.

      figure.png

      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

      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.

  • +

    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
    • +

      P2.17-08 - Heart Motion in Lung Radiotherapy: How Representative Are Delineations Based on 3DCT, Average and Maximum Projection Scans? (ID 13946)

      16:45 - 18:00  |  Author(s): Eliana Vasquez Osorio

      • Abstract
      • Slides

      Background

      Evidence is emerging that the heart is more radiosensitive than previously assumed [1-2]. However, only delineations on the average projection or 3D CT scans are used for treatment planning. Therefore the motion of this organ due to respiration and contraction is not accounted for. In this pilot study, we assessed how representative the delineations based on the 3D CT scan, average (AVG) and maximum intensity projections (MIP) are.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Both 3D and 4D CT scans for 7 lung cancer patients treated by SABR were used in this study. Median delineations, derived from 3 independent observers following a previously agreed protocol, were calculated on the 3D CT, AVG, MIP and 25% exhale scans.

      Delineations on each 4D phase scan (n=8) were created by propagating the median 25% exhale contours using RayStation v5.99. The volume representing the maximum extent of motion was estimated as the union of all 4D phase delineations (U4D). Surface distances from the U4D to 3D, AVG, MIP volumes were calculated. Distances in the most extreme surface points (1cm most superior/inferior, 10% most right/left/anterior/posterior) are reported.

      4c3880bb027f159e801041b1021e88e8 Result

      Figure 1 shows the distances for the most extreme surface points, for all patients and for each delineation. Patterns vary widely among patients. From the three delineations, MIP is the ‘closest’ to the maximum extent of motion, followed by AVG and 3D.

      fig.png

      8eea62084ca7e541d918e823422bd82e Conclusion

      None of the delineations represented the heart’s maximum extent of motion for all patients, the MIP being the ‘most representative’ volume. All delineations would require an expansion to include all motion. Research including dosimetry measurements and inter-observer variability is required to determine the relevance of expanding the original delineations, and the corresponding margin magnitudes.

      [1] Johnson et al. Radiotherapy & Oncology. 2018. Volume 127:S170-1
      [2] Wang et al. J Clin Oncol. 2017. 35(13):1387-94.

      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.