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Michael A. Pritchett



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    MA13 - Interventional Pulmonology (ID 914)

    • Event: WCLC 2018
    • Type: Mini Oral Abstract Session
    • Track: Interventional Diagnostics/Pulmonology
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/25/2018, 10:30 - 12:00, Room 206 AC
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      MA13.10 - Comparison of Pulmonary Nodule Location Between Preprocedural CT and Intra-Procedural Cone-Beam CT During Guided Bronchoscopy (ID 14216)

      11:35 - 11:40  |  Presenting Author(s): Michael A. Pritchett

      • Abstract
      • Presentation
      • Slides

      Background

      Electromagnetic navigation bronchoscopy relies on pre-procedural CT scans to create a virtual airway reconstruction that is used as a roadmap during bronchoscopy. These systems assume similarity between the position of the nodule during bronchoscopy and the pre-procedure CT scan. However, there are multiple factors that suggest that such assumption maybe inaccurate. These include differences in positioning, breathing motion, and the presence of atelectasis. In this study, we evaluated the lung nodule position between pre-procedural CT to interprocedural cone-beam CT (CBCT). In addition, we assessed the ability of a novel augmented endobronchial fluoroscopic guidance system (LungVision, Body Vision Medical Ltd, Israel) to overcome those differences in real-time.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      This was a prospective study of 21 patients with 23 peripheral pulmonary nodules. CT scans were imported into the planning software and the physician identified the nodule and navigation pathway. CBCT (Philips Allura Xper FD20) was used to scan the patient during the procedure. LungVision was used for real-time navigation and guidance during biopsy. The divergence in nodule location between the pre-procedural CT and the interprocedural CBCT was measured.

      4c3880bb027f159e801041b1021e88e8 Result

      The average patient age was 69 ± 8.6, median nodule size was 18mm with 74% of the nodules in the upper lobes. The average divergence of the nodule was 14.11 ± 9.9mm. Successful navigation was verified by CBCT in 91% of cases. Malignancy was diagnosed in 20 of 23 nodules for a diagnostic yield of 87%. No adverse events were reported.

      8eea62084ca7e541d918e823422bd82e Conclusion

      This study demonstrates a significant divergence in lesion location between pre-procedural CT and intra-procedural CBCT during guided bronchoscopy. This finding indicates that the change in nodule position between the CT and bronchoscopy could have a great impact on the diagnostic success of the procedure. This movement, sometimes greater than the size of the nodule itself, can lead to an inaccurate localization when relying solely on virtual bronchoscopic or electromagnetic navigation.

      CT to patient divergence does not appear to influence the accuracy of this novel navigation platform. The system is capable of tracking the nodules dynamically and can compensate for changes in patient positioning and respiratory motion during both navigation and biopsy which leads to a high diagnostic yield.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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    MA16 - Novel Mechanisms for Molecular Profiling (ID 917)

    • Event: WCLC 2018
    • Type: Mini Oral Abstract Session
    • Track: Advanced NSCLC
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/25/2018, 13:30 - 15:00, Room 203 BD
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      MA16.02 - Prospective Clinical Validation of the InVisionFirst™ ctDNA Assay for Molecular Profiling of Patients with Advanced NSCLC (ID 13885)

      13:35 - 13:40  |  Author(s): Michael A. Pritchett

      • Abstract
      • Presentation
      • Slides

      Background

      Clinical practice guidelines advocate molecular profiling as a part of the evaluation of advanced NSCLC, with ctDNA based profiling being an option for those with insufficient tissue. Thorough prospective clinical validation studies of NGS based ctDNA assays are lacking. Here we report the multi-centered prospective clinical validation of a ctDNA NGS panel for stratification of patients with advanced untreated NSCLC.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      InVisionFirst™ (Inivata) is a ctDNA NGS assay for detection of genomic alterations in 36 genes commonly mutated in NSCLC and other cancers. 264 patients with untreated advanced NSCLC were prospectively recruited by 41 US centers. 178 patients had tumour tissue available for molecular profiling (predominantly by NGS) and the remaining 86 patients without tissue were included to compare ctDNA profiles obtained from patients with and without tissue for profiling.

      4c3880bb027f159e801041b1021e88e8 Result

      A total of 204 patients (77.3%) had detectable ctDNA alterations. Using tissue results as the reference, overall concordance for the full 36 genes in the InVisionFirst™ panel with matched tissue profiling was 97.8% with 82.9% PPV, 98.5% NPV, 70.6% sensitivity and 99.2% specificity. Considering a subgroup of 8 genes that can influence routine clinical patient management (EGFR, ALK, ROS1, ERBB2, MET, BRAF, KRAS, STK11) the PPV was 93.7%, 96.8% NPV, 72.4% sensitivity and 99.4% specificity. Excluding patients with undetectable ctDNA, these figures become 93.7% PPV, 98.4% NPV, 87.3% sensitivity and 99.3% specificity. The observed pattern of genomic changes seen in ctDNA was consistent across patients with and without tissue for profiling. Across the whole study, 44 patients with actionable alterations were identified by ctDNA testing compared to only 36 by tissue testing. 47% of patients tested by ctDNA had an actionable alteration or an alteration that is generally mutually exclusive for such actionable changes such as KRAS or STK11.

      8eea62084ca7e541d918e823422bd82e Conclusion

      The InVisionFirst™ assay demonstrates excellent concordance with tissue profiling in this multi-centered prospective clinical validation study. The performance of this assay in terms of overall sensitivity and specificity appears comparable if not higher than other established commercial ctDNA assays. Utilization of InVisionFirst™ ctDNA testing led to the detection of 22% more actionable alterations than standard of care tissue testing in this study supporting its use for the molecular stratification of patients with advanced NSCLC. Further analyses on the features associated with detectable ctDNA signatures are ongoing.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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    P1.05 - Interventional Diagnostics/Pulmonology (Not CME Accredited Session) (ID 937)

    • Event: WCLC 2018
    • Type: Poster Viewing in the Exhibit Hall
    • Track:
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall
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      P1.05-06 - Bronchoscopic Image-Guided Microwave Ablation of Peripheral Lung Tumours – Early Results (ID 14420)

      16:45 - 18:00  |  Author(s): Michael A. Pritchett

      • Abstract
      • Slides

      Background

      Thermal ablation is indicated for the treatment of early lung cancer in medically inoperable patients, and for oligometastatic disease. However, percutaneous ablation is associated with 30-50% pneumothorax, haemothorax, pleural effusion and pain. Peripheral lung tumours can be reached by electromagnetic navigation bronchoscopy (ENB) without breaching the pleura. Intraprocedural cone-beam CT (CBCT) and transbronchial access instruments allow lesions in the lung periphery to be reached with accuracy. Another advantage of the bronchoscopic approach is the ability to concurrently obtain tissue for diagnosis and molecular characterization, and to perform full nodal staging.

      Bronchoscopic radiofrequency ablation (RFA) has been described for tumours with positive bronchus sign, but the effectiveness of RFA is limited by impedence of air and heat-sink effects of vessels. Microwave avoids these limitations.

      We present our early experience of bronchoscopic microwave ablation of tumours with CBCT guidance and transbronchial access.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      ENB (Superdimension, Medtronic, Minneapolis) was carried out under general anaesthesia. A CBCT (Philips, Eindhoven) confirms probe position and its relationship to the lesion. Transbronchial access with CrossCountry device (Medtronic, Minneapolis) was used as required to reach extrabronchial lesions. A flexible microwave ablation catheter (Emprint, Medtronic) was advanced to the lesion. Ablation was planned with OncoSuite (Philips, Eindhoven) to ensure the ablation zone encompassed the lesion with a 5mm margin. Ablation was carried out and a fiducial was placed at the ablation site to facilitate follow-up. A control CBCT was carried out post procedure.

      4c3880bb027f159e801041b1021e88e8 Result

      Between February and April 2018, three patients (2F:1M, mean age 70.3) with oligometastatic disease (2 colorectal, 1 endometrial) underwent bronchoscopic microwave ablation to 4 lung lesions (two RLL nodules (in one patient), LUL and LLL, median size 10.5mm (range 7-13mm), 3 without bronchus sign). All lesions were reached, with the LUL nodule requiring transbronchial access. All lesions were treated at 100W for 10 minutes.

      CBCT confirmed ground-glass opacification of the ablation zones encompassing the lesions. There were no procedural complications, pneumothorax or bleeding. Two patients with lesions close to the pleura experienced mild, localised chest discomfort which resolved by 24 hours. All patients were discharged the following day. A CT at 30 days for the first patient showed a 25x32mm area of dense ovoid consolidation representing the ablation zone, with no complications.

      8eea62084ca7e541d918e823422bd82e Conclusion

      Our early experience shows bronchoscopic microwave ablation is safe and feasible with low morbidity. The accuracy of the procedure is enhanced by CBCT control. Lesions remote from the bronchial tree could be accessed and safely treated.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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    P2.01 - Advanced NSCLC (Not CME Accredited Session) (ID 950)

    • 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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      P2.01-78 - Validation of InVisionFirst ctDNA NGS Profiling via ddPCR Testing in Patients with Non-Small Cell Lung Cancer (NSCLC) (ID 12220)

      16:45 - 18:00  |  Presenting Author(s): Michael A. Pritchett

      • Abstract
      • Slides

      Background

      Tumor tissue based molecular profiling is widely utilized to guide therapy in advanced NSCLC and recently, ctDNA assays have been developed to detect actionable alterations in a non-invasive manner. However, there are frequent reports of discordance between analysis platforms and here we compare the Inivata NGS ctDNA assay with ddPCR based ctDNA analysis and tissue NGS sequencing in patients with advanced NSCLC.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      InVisionFirst (Inivata) is a ctDNA NGS assay for detection of genomic alterations in 36 genes commonly mutated in NSCLC and other cancer types. A cohort of 52 patients underwent ctDNA analysis by InVisionFirst and were tested in a blinded manner for 4 actionable gene alterations (EGFR L858R & Ex19del, KRAS G12C & G12D) and 30 of the cohort also had testing for 5 additional alterations (EGFR T790, EML4-ALK fusions, ROS1 fusions, KRAS G12V and BRAF V600E) at one of two independent ddPCR laboratories. Finally, tissue analysis by NGS was available in 21 patients to arbitrate any discordance between the results of the 2 liquid biopsy techniques.

      4c3880bb027f159e801041b1021e88e8 Result

      Across the 9 specific genetic alterations investigated by both ctDNA platforms, 26 alterations were detected by the InvisionFirst platform and 23 were detected by the ddPCR platforms. The overall concordance of gene alterations was 98.5% (320/342) with positive agreement of 95.5% and negative agreement of 98.8%. Discordance was observed in 6 detected gene alterations, with 1 EML4-ALK fusion, 1 EGFR exon19 deletion and 2 KRAS G12Cs being detected by InVisionFirst but not by ddPCR, and 1 EGFR L858R and 1 KRAS G12D detected by ddPCR but not InVisionFirst. One G12C, the EML4-ALK, and the L858R alteration were confirmed by tissue NGS. The KRAS G12D was not confirmed by tissue NGS. No tissue was available to examine for the detection of the EGFR exon 19 deletion or the other KRAS G12C mutation. All other results were concordant.

      8eea62084ca7e541d918e823422bd82e Conclusion

      This study in NSCLC patients demonstrates excellent concordance of the InVisionFirst ctDNA NGS assay with ddPCR based ctDNA analysis via blinded independent laboratories. The excellent sensitivity and specificity support the use of the InVisionFirst assay as a non-invasive “liquid biopsy” for molecular profiling.

      6f8b794f3246b0c1e1780bb4d4d5dc53

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