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R. Macrae



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    P1.08 - Poster Session 1 - Radiotherapy (ID 195)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Radiation Oncology + Radiotherapy
    • Presentations: 1
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      P1.08-027 - Is there a benefit of lung stereotactic ablative radiotherapy (SABR) in our patients with multiple co-morbidities?: Age-adjusted Charlson Comorbidity Index (ACCI) as a predictor of survival in medically inoperable early stage Non Small Cell Lung Cancer patients treated with definitive radiotherapy (ID 3392)

      09:30 - 09:30  |  Author(s): R. Macrae

      • Abstract

      Background
      The Age-adjusted Charlson Comorbidity Index (ACCI) was originally developed as a tool to predict survival for a wide range of patients based on their co-morbidities. As a growing proportion of Stage I non-small cell lung cancer (NSCLC) patients are treated with radiotherapy alone, in part due to extensive comorbidities, we hypothesize that a) ACCI is a useful prognostic tool for this understudied group of patients and b) the advent of stereotactic ablative radiotherapy (SABR) has lead to a redistribution of patients such that more patients of the poorest class are now treated, with similar or better survival.

      Methods
      A single institution, ethics-approved database with outcome data for 406 Stage I NSCLC patients treated with curative radiotherapy alone from 2001 to 2011 was queried. 283 patients were treated with conventional radiotherapy and 123 with SABR. Conventional doses ranged from 50-60Gy over 15-30 fractions, SABR 48-60Gy over 3-8 fractions. For each patient the ACCI score was retrospectively calculated and then arbitrarily stratified into 3 groups based on score ( ≤3, 4-5, ≥6) (higher score indicates higher number of comorbidities). Log rank test and Kaplan-Meier survival analyses was performed and the relationship between ACCI and survival was assessed using proportional hazards analysis.

      Results
      Median follow up was 26.4 months (22.8 months in the SABR group). The median patient age at treatment was 75 (range 41 to 92) for the entire cohort and for the SABR subset 74 (range 54-89). Percentage of patients by ACCI grouping was 22% (≤3), 48% (4-5) and 30% (≥6) for the entire cohort and for the SABR subset was 21% (≤3), 59% (4-5) and 20% (≥6) (p> 0.05). The median overall survival (OS) from time of diagnosis was 39.6 months (95% CI 34.8-44.4) and by ACCI groupings (≤3, 4-5, ≥6) was 51.6, 39.6 and 30 months (log rank test p=0.023) with hazard ratios for survival of 1.00, 1.45 (p = 0.049) and 1.73 (p = 0.0067) respectively. In the subset of patients treated with SABR, median OS was 46.8 months however there is lack of power to demonstrate any OS difference between ACCI groups.

      Conclusion
      The ACCI is predictive of overall survival in medically inoperable Stage I NSCLC patients irradiated with curative intent. The benefit of radiation is evident in even the poorest of patients (CMI ≥6) with a median survival of 30 months exceeding what one would expect without any treatment at all. Further follow up will be required to comment on any increased benefit with SABR.

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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): R. Macrae

      • 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.