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H. Roberts



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    O06 - Cancer Control and Epidemiology I (ID 135)

    • Event: WCLC 2013
    • Type: Oral Abstract Session
    • Track: Prevention & Epidemiology
    • Presentations: 1
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      O06.06 - Factors Associated with Smoking Cessation in Participants of The Pan Canadian Early Lung Cancer Study (ID 1469)

      11:35 - 11:45  |  Author(s): H. Roberts

      • Abstract
      • Presentation
      • Slides

      Background
      Lung cancer screening programs provide unique opportunities to facilitate smoking cessation in smokers who participate in these programs. However, the effects of screening on motivation to quit might be mediated or modified by other variables. Identifying the participants more likely to quit will allow rapid application of smoking cessation resources to these participants, while those least likely to quit can be afforded experimental interventions. The aim of our study was to assess the impact of lung cancer screening on smoking cessation in current smokers at the time of enrollment and to identify factors that were associated with quitting smoking in this screening population.

      Methods
      Using data collected from the Pan-Canadian Study of Early Detection of Lung Cancer, both univariate and multivariable logistic regression analysis was used to identify predictors of smoking cessation among current smokers at enrolment. Smoking cessation was defined as quitting for at least a 6 month period, occurring anytime after enrolment.

      Results
      We analyzed baseline and follow-up questionnaires of 2320 participants, of which 1419 were current smokers. Of these 1419 patients, 392 (27.8%) met the definition of smoking cessation during a median of two annual follow-up visits. In both univariate and multivariable (MV) analysis, greater smoking cessation was associated with four factors: (i) having a diagnosis of lung cancer at any time during the screening process, with a MV Odds ratio (OR) of quitting of 2.4 (95%CI: 1.1-5.0); (ii) lower and medium nicotine addiction as assessed by the Fagerström Nicotine Dependence Scale Score, with MV-ORs of 3.2 (95%CI: 2.2-4.6) and 1.4 (95%CI: 0.9-2.0), respectively; (iii) having higher education, with MV-OR: 1.4 (95%CI: 1.1-1.9); and (iv) having an earlier age of onset of regular alcohol intake, with MV-OR of 1.11 (95%CI: 1.02-1.21) per 5 year decrease in age. Smoking cessation was also associated with (i) previous attempts of quitting [UV-OR 1.8 (95%CI: 1.2-2.7)], willingness to quit smoking within the next month (at baseline screening) [UV-OR 2.2 (95%CI: 1.8-2.9)] or within the next 6 months after baseline screening [UV-OR 1.8 (95%CI: 1.3.-2.4)]. Second-hand smoking exposure, including exposure as a child, or as an adult at work, at home, privately with friends, or in public settings, or a cumulative index of these different exposures, was not associated with smoking cessation. Presence of potential index symptoms for lung disease, including shortness of breath, cough (both dry and productive), hoarseness, audible wheezing or even chest pain, was not associated with an increased chance of smoking cessation.

      Conclusion
      The diagnosis of a new lung cancer had a major positive impact on screening participants quitting smoking, as were factors such as lower nicotine dependence, higher education, earlier starting alcohol drinking age, and willingness to quit. Whether a new lung cancer diagnosis triggered additional efforts by clinicians to help the person quit will be explored further. Individual lung symptoms and secondhand smoke exposure were not associated with smoking cessation. (Geoffrey Liu and Martin Tamemmagi are co-senior authors)

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    O10 - Stereotactic Ablative Body Radiotherapy (ID 104)

    • Event: WCLC 2013
    • Type: Oral Abstract Session
    • Track: Radiation Oncology + Radiotherapy
    • Presentations: 1
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      O10.06 - Inter-Rater Reliability of the Categorization of Late Radiographic Changes after Lung Stereotactic Body Radiation Therapy (SBRT) (ID 1901)

      17:10 - 17:20  |  Author(s): H. Roberts

      • Abstract
      • Presentation
      • Slides

      Background
      Radiographic changes following lung SBRT have been previously categorized into 4 groups: modified conventional pattern (A), mass-like fibrosis (B), scar-like fibrosis (C) and no evidence of increased density (D) (Dahele et al.).The purpose of this study was to assess the inter-rater reliability of this categorization in patients with early stage non-small cell lung cancer.

      Methods
      79 patients treated with SBRT for early stage NSCLC at a single institution who had a minimum follow-up of 6 months were included in this study. Serial post-treatment CT images were presented to expert clinicians (up to 6) familiar with post-SBRT radiographic changes and were scored by each individual in a blinded fashion according to the published categorization of A, B, C or D. The proportion of patients categorized as A, B, C or D at each interval was determined. Krippendorff's alpha (KA) was used to establish inter-rater reliability at each time point. A leave-one-out analysis was performed at each time point on each rater to determine the sensitivity of the KA score to an individual rater. To explore if a training effect existed the KA of the first and last 20 patients scored by the raters was determined.

      Results
      There were 351 ratings on 67 patients at 12mo, 250 ratings on 49 patients at 24mo, 169ratings on 31 patients at 36mo and 80 ratings on 14 patients at 48mo. The proportion of patients scored in each category of A,B,C &D is reported in Table 1. Table 1: Scale Category by Time-Point

      A (Modified-Conventional) B (Mass-like Fibrosis) C (Scar-like Fibrosis) D (No Evidence of Increased Density)
      6 months 43% 9% 6% 42%
      12 months 50% 16% 11% 23%
      18 months 46% 18% 16% 20%
      24 months 46% 22% 17% 15%
      36 months 40% 24% 21% 15%
      48 months 29% 24% 31% 16%
      Category A was the most common at all time points except 48 months when category C was the most common. KA was 0.28, 0.27, 0.18 and 0.27 at 12, 24, 36 and 48 months respectively. The range of KA in the leave-one-out analysis was 0.25-0.31, 0.24-0.27, 0.15-0.22 and 0.24-0.31 at 12, 24, 36 and 48 months respectively. The KA of the first 20 patients vs the last 20 patients was 0.34 vs 0.47 at 12 months.

      Conclusion
      The predominant pattern of post SBRT radiographic changes evolves over time. In this study categorization of late post-SBRT radiographic changes has moderate inter-rater agreement. There is a suggestion of a training effect with more experience. However, categorization of late radiographic changes following SBRT is challenging and may require specific training.

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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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      P1.08-019 - Late Radiographic Changes After Lung Stereotactic Body Radiotherapy: Piloting a Recurrence Scale and a Synoptic Reporting Scale (ID 2209)

      09:30 - 09:30  |  Author(s): H. Roberts

      • Abstract

      Background
      Radiographic lung changes after Stereotactic Body Radiotherapy (SBRT) for non-small cell lung cancer (NSCLC) are difficult to interpret. The reliability of previous scoring systems and their relationship to local failure has not been assessed. The purpose of this study was to design a synoptic radiographic scale for characterizing late radiographic changes after SBRT and to determine the inter-rater reliability of the scale.

      Methods
      A Recurrence Scale (RS) was developed among lung radiation oncology/SBRT experts at a single institution, and a Synoptic Radiographic Scale (SRS) was designed in collaboration with an expert thoracic radiologist. For the RS, the suspicion for local recurrence on CT images was scored on a 5 point scale: 1) complete response, no recurrence; 2) fibrosis, not suspicious for recurrence; 3) fibrosis/mass, indeterminate for recurrence; 4) fibrosis/mass, suspicious for recurrence and 5) biopsy proven recurrence. On the SRS, CT changes were scored as ‘increasing’, ‘stable’, ‘decreasing’, ‘no change’ or ‘obscured’, along five dimensions: changes in the primary tumor site, involved lobe, consolidation, ground-glass opacity, and volume loss. Early stage NSCLC patients treated with SBRT at the institution with a minimum follow-up of 6 months were included. Serial post-treatment CT images at 12, 18, 24, 36, and 48 months were presented to the expert group (up to 6) who scored both scales in a blinded fashion. Krippendorff's alpha (KA) was used to assess inter-rater reliability. The association between RS score and known local failure was compared using Fisher’s Exact Test. The association between ‘growing tumor’ on the SRS and known local failure was compared using Fisher’s Exact Test.

      Results
      79 patients were scored; 7 of them had documented local failures. Experts did 11243 scorings in total, ranging from 2351 at 6 months to 480 at 48 months. For the RS, the KA was 0.27, 0.36, 0.23 and 0.45 at 12, 24, 36 and 48 months respectively. For the SRS, KA was 0.22, 0.14 and 0.11 for the treated tumor at 12, 24 and 48 months and 0.33, 0.36 and 0.22 for consolidation at 12, 24 and 36 months. The tumor was scored as obscured in 40% of patients by 24 months. Of patients with local failure, 71% were at least once scored as ‘suspicious for recurrence’ by at least one rater, compared to 28% in patients without failure (p = 0.03). 86% of patients with failure were scored at least once as increased opacity in tumor site by at least one of raters, compared to 35% in patients without failure (p = 0.01).

      Conclusion
      The RS has a significant relationship with local failure, and there is fair inter-agreement among experts on the suspicion of recurrence following SBRT. The SRS has low inter-rater reliability. Among its categories, only an increase in the opacity of treated tumor site is significantly related to failure. With future refinement of SRS categories, it can be a useful tool to standardize post-SBRT radiology reporting.

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    P3.20 - Poster Session 3 - Early Detection and Screening (ID 174)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Imaging, Staging & Screening
    • Presentations: 1
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      P3.20-003 - A Practice Guideline for Low Dose CT Screening for Lung Cancer: Evidence Based Recommendations Before Implementation. (ID 1197)

      09:30 - 09:30  |  Author(s): H. Roberts

      • Abstract

      Background
      The National Lung Screening Trial (NLST) compared low dose CT (LDCT) with chest radiography (CXR) in high-risk populations and found a 20% reduction in lung cancer mortality at 6 years with LDCT after an initial scan and two annual rounds of screening. This is the first randomized controlled trial (RCT) to show a mortality benefit with lung cancer screening. LDCT screening is not yet part of the standard of care and no formal process currently exists in Ontario, Canada for lung cancer screening. Injudicious use of LDCT can potentially cause more harm than benefit, including exposure of healthy persons to ionizing radiation and subsequent invasive procedures for ultimately benign lesions. When used correctly, however, LDCT screening has the potential to save lives. A practice guideline was developed to guide clinicians and healthcare policy makers with evidence-based recommendations for screening high-risk populations for lung cancer.

      Methods
      The guideline was developed using the methods of Cancer Care Ontario’s Program in Evidence-Based Care (PEBC). The core methodology of the PEBC’s guideline development process is a systematic review. A systematic review had recently been completed by a collaboration of the American Cancer Society, the American College of Chest Physicians, the American Society of Clinical Oncology, and the National Comprehensive Cancer Network. The evidence from that systematic review formed the basis of the current recommendations, which were reviewed, and amended where necessary, by clinical experts in the fields of medical, radiation, and thoracic oncology; diagnostic radiology; pulmonary disease; and population health. The recommendations were reviewed by the Provincial Lung Cancer Disease Site Group and underwent both internal review by an expert panel and external review by clinicians with expertise in the topic to achieve consensus.

      Results
      The systematic review included three RCTs comparing LDCT screening with CXR (including the NLST), 5 RCTs comparing LDCT screening with usual care (no screening), and 13 single-arm studies of LDCT in patients at risk for lung cancer. One large RCT reported a statistically significant reduction in lung cancer mortality with low-dose computed tomography at six years compared with CXR. The practice guideline recommendations generally align with the parameters of the NLST. Deviations were described and justified by the guideline working group. The recommendations support screening persons at high-risk for lung cancer with advice for defining a positive result on LDCT, appropriate follow-up, and optimal screening interval.

      Conclusion
      The benefits of screening high-risk populations for lung cancer with LDCT outweigh the harms if screening is implemented in a strictly controlled manner targeting the high risk population. This practice guideline forms the basis for the rationale for a screening program. An economic impact analysis will need to be done to design an appropriate cost effective lung cancer screening program prior to implementation.