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J. Pantarotto



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    P2.12 - Poster Session 2 - NSCLC Early Stage (ID 205)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Medical Oncology
    • Presentations: 1
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      P2.12-023 - Pre-treatment 18FDG-PET SUV<sub>max </sub>As A Predictor of Distant Metastasis in Early Stage NSCLC Treated with Definitive Radiotherapy (ID 3442)

      09:30 - 09:30  |  Author(s): J. Pantarotto

      • Abstract

      Background
      Positron emission tomography (PET) using [[18]F]-fluoro-2-deoxy-glucose (FDG) is a standard staging investigation for patients with non-small cell lung cancer (NSCLC). The maximum standardized uptake value (SUV~max~) is a semi-quantitative measure of FDG uptake that correlates with tumor doubling time and proliferation rates, which in turn are known to correlate with tumor aggressiveness. The aim of this study was to determine whether the pre-radiation SUV~max~ of the primary tumor for FDG has a prognostic significance in patients with T1 or T2N0 NSCLC treated with curative radiation therapy.

      Methods
      Between April 1993 and December 2011, a total of 406 patients with medically inoperable histologically proven T1 or T2N0 NSCLC treated with radiotherapy (either conventional fractionation or stereotactic ablative radiotherapy (SABR)) were entered in an ethics-approved database. Minimum radiation dose delivered was 50Gy. 180 tumors (163 patients) with pre-treatment FDG-PET/CT scan satisfied the eligibility criteria. We stratified the patients above and below the median SUV~max~ value on the pre-treatment PET/CT scan and analysed the survival data, measured from date of diagnosis. Statistical analysis (including multivariate) was done using SPSS v15. Survival data was analysed using Kaplan-Meier method, and comparisons of survival were done using Mantel-Cox log-rank test.

      Results
      Of the 180 tumors, 68.9 % were T1; 24.6% centrally located (RTOG definition); 64.4% of treated with SABR. Median follow-up time was 15 months. Overall survival (OS) at 2 and 3 years for the entire cohort was 76% and 67% respectively. Mean and median SUVmax were 8.1 and 7 respectively. Progression free survival at 3 years with SUVmax < 7 was approximately double that of those patients with tumor SUVmax ≥ 7 (55% vs. 28%; p=0.0096). Tumors with SUVmax ≥ 7 were associated with a worse regional recurrence free survival but no difference was seen for local recurrence. In the multivariate analysis SUVmax≥7 was an independent prognostic factor for distant metastasis free survival (DMFS) [Figure 1], in addition to a higher T status being an independent prognostic factor for worse overall survival. Figure 1: Results of univariate and multivariate analysis demonstrating the prognostic factors associated with DMFS Figure 1

      Conclusion
      In early stage NSCLC managed with radiation alone, patients with high SUV~max~ ≥7 on FDG-PET/CT scan have poorer outcomes and high risk of progression, possibly due to aggressive biology. Pre-treatment FDG-PET/CT is an effective and non-invasive method to identify patients with higher risk of distant metastasis and possible candidates for adjuvant therapy studies.

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    P3.08 - Poster Session 3 - Radiotherapy (ID 199)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Radiation Oncology + Radiotherapy
    • Presentations: 1
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      P3.08-007 - Stereotactic Ablative Radiotherapy (SABR) of Centrally Located Early Stage Lung Cancer Accrued to RTOG 0813: Novel Scoring System to Compare Plan Quality of Volumetric Modulated Arc Therapy (VMAT) versus Robotic Radiosurgery (ID 1068)

      09:30 - 09:30  |  Author(s): J. Pantarotto

      • Abstract

      Background
      Central lung tumours pose a challenge for stereotactic ablative radiotherapy (SABR) due to proximity to vital organs and risk of potentially fatal toxicity. RTOG 0813 is an attempt to determine a safe dose for these tumours in an era where many institutions have multiple technologies that can deliver lung SABR. The purpose of this study is to use a novel scoring system to compare two different SABR platforms, robotic radiosurgery (RRS) and linac-based volumetric modulated arc therapy (VMAT), in a cohort of patients actually treated on 0813. The comparison is limited to target coverage and organ-at-risk (OAR) sparing capability for this technically challenging group of patients.

      Methods
      All 5 patients from our institution accrued to RTOG 0813 were selected for this study. Eight planners (4 VMAT, 4 RRS) with combined experience of >500 lung SABR cases re-planned each case for 60 Gy in 5 fractions. Patient setup, contouring details, and planning constraints were as per 0813. Monte Carlo planning was performed on Monaco v3.20 (Elekta Inc., MI, USA) for VMAT and Multiplan v4.5.0 (Accuray Inc., Sunnyvale, USA) for RRS on CyberKnife. An objective scoring system was designed that included each dose-volume 0813 protocol criterion. For each target requirement or OAR constraint a “structure score” was assigned whereby [Actual Plan parameter /Expected 0813 parameter] X priority factor = structure score. Priority factors (high 0.9, intermediate 0.6, and low 0.3) were assigned by 3 experienced lung SABR radiation oncologists for each of the 5 patients given that different OARs were of greater concern depending on exact target location. A ‘final plan score’ was the sum of all structure scores, with a lower overall score indicating a plan that best achieved target coverage and OAR avoidance in keeping with radiation oncologist priority. To reduce inter-planner bias more than one plan was created for each of the 5 patients using both modalities and only the best plans were selected for comparison.

      Results
      A total of 15 VMAT and 10 RRS plans were submitted for analysis, each satisfying the minimum 0813 protocol requirements. Using the scoring system, a final plan score was obtained for all 25 plans with a median VMAT score of 8.02 (range 5.52 to 10.09) and RRS score of 7.1 (range 4.98 to 12.41). The lowest scoring VMAT plan was then compared with the lowest scoring RRS plan for each patient. Analysis of target coverage parameters showed that both modalities had similar scores, indicating an equivalent ability to conformally cover the target. RRS plans had lower OAR scores (mean reduction of 1.3) compared to VMAT plans. Overall the plan scores for each patient (RRS: VMAT) were: Patient 1 (6.74:9.2), Patient 2 (6.69:7.32), Patient 3 (4.98:5.94), Patient 4 (7.69:8.92), Patient 5 (5.78:7.36).

      Conclusion
      When using a scoring system based on RTOG 0813 planning criteria to compare patient plans from two different lung SABR delivery systems, 5 of 5 patients planned using a robotic radiosurgery system had more favourable overall scores compared to VMAT linac delivery for centrally located tumours.

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    P3.09 - Poster Session 3 - Combined Modality (ID 214)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Combined Modality
    • Presentations: 1
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      P3.09-006 - Outcomes of Elderly Patients with Locally-Advanced Non-Small Cell Lung Cancer (LA-NSCLC) Treated with Radiation +/- Chemotherapy at the Ottawa Hospital Cancer Centre (ID 1331)

      09:30 - 09:30  |  Author(s): J. Pantarotto

      • Abstract

      Background
      Concurrent chemoradiation (C-CRT) is standard therapy for fit patients with unresectable, LA-NSCLC. We evaluated outcomes of patients treated with curative intent at our centre for quality assurance, and to compare outcomes between elderly (≥75) and younger patients.

      Methods
      Patients with stages IIIA/ IIIB NSCLC from 2002 to 2008 were identified, and those planned for curative-intent radiation (minimum 50Gy) included, irrespective if therapy was actually completed. Charts were reviewed for patient demographics, baseline prognostic factors, treatments planned and administered, hospitalizations and outcomes. Multivariable analyses were performed to determine factors associated with survival.

      Results
      329 patients were included: median age 66 (range 40-89), 60% male, 15% ECOG 2+, 60% IIIB, 35% weight loss >5%. 20% (66/329) were ≥75. C-CRT, sequential CRT and radiation alone were delivered in 85%, 5%, and 10% of cases, respectively; the elderly were less likely to receive C-CRT (61% vs. 91%). Median survival (all patients) was 18.4 months; for < and ≥75 cohorts, MS were 20.8 and 16.4 months (p=0.0533). 3 and 5 year OS (all patients) were 29% and 17%; for the < and ≥75 cohorts values were 31/21% and 19/8%. Elderly patients had lower treatment-related hospitalization (6% vs. 20%) and death (2% vs. 5%). Radiation compliance was equivalent however chemotherapy completion was higher in younger patients (78% vs. 45%). In multivariate analysis, age ≥75 (HR=1.68, 95% CI 1.03-2.75, p=0.038), female gender (HR=0.60, 95% CI 0.41-0.87, p=0.008), and completion of radiation therapy (HR=0.39, 95% CI 0.25-0.62, p<0.0001) were independent predictors of outcome. Figure 1

      Conclusion
      Outcomes of patients with LA-NSCLC offered curative therapy at the Ottawa Hospital Cancer Centre are comparable to those obtained in clinical trials of C-CRT, despite a more unselected population with a higher proportion of poor prognostic features. Those ≥75 were less likely to be offered C-CRT and were less likely to complete planned chemotherapy. However fit patients ≥75 offered radical therapy still have reasonable MS and 3-year OS.