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N. Ahmed



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    P2.08 - Poster Session 2 - Radiotherapy (ID 198)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Radiation Oncology + Radiotherapy
    • Presentations: 1
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      P2.08-008 - A prospective study to determine inter-observer variability of Gross Tumor Volume with FDG-PET/CT compared to CT alone in Stage III Non-Small Cell Lung Cancer using Three-dimensional Analysis. (ID 1086)

      09:30 - 09:30  |  Author(s): N. Ahmed

      • Abstract

      Background
      There are no randomized trials comparing CT versus FDG-PET/CT based radiotherapy planning for lung cancer or any other disease site.Based on phase II studies, a convincing body of data has emerged within the last 10 years incorporating the use of FDG-PET scans for radiotherapy planning in lung cancer.Published data comparing changes in volume measured with FDG-PET/CT to CT alone indicates that the magnitude of treatment volume changes with incorporation of PET in radiotherapy planning for lung cancer varies from 27% - 100%. However, volumetric data only provides information on changes in size and does not account for potential changes in position and shape of the target, thereby affecting variability of the GTV in NSCLC. In this study we describe influence of FDG-PET/CT or CT alone for the primary and mediastinal nodal disease in radiation planning for stage III NSCLC in relation to changes in volume, position and overlap of the GTV. We also report the interobserver variability between radiation oncologists for FDG-PET/CT and CT alone-derived GTV. In addition to volumetric measurements, we have used a vector displacement method for three-dimensional (3D) positional analysis. We have further evaluated the overlap of the primary and nodal GTV with Dice Similarity Coefficient (DSC) method

      Methods
      Patients (n=29) underwent Three Dimensional Conformal Radiotherapy (3DCRT) planning by three different radiation oncologists. Simultaneous co-registered CT and FDG-PET/CT were obtained in the same treatment planning position. Gross Tumor Volume (GTV) for lung tumor and mediastinal lymphadenopathy was contoured and compared for changes in volume and position. Interobserver variability was determined using three-dimensional analysis with vector displacement and the Dice Similarity Coefficient (DSC). Concordance for the number of lymph nodes contoured was performed.

      Results
      Mean GTV for lung tumor with FDG-PET/CT and CT alone was 62.0 cm[3] and 74.64 cm[3], respectively (p=0.0005), resulting in a 17% reduction by FDG-PET/CT. Mean GTV for mediastinal lymphadenopathy was 15.72 cm[3] and 19.02 cm[3] (p=0.084), equalling a 17% reduction GTV for FDG-PET/CT. Mean vector displacement of lung tumor was 2.0 mm with FDG-PET/CT versus 7.1 mm with CT alone (p = 0.0016), equating to a 3.6 fold reduction in interobserver variability of position. Mean vector displacement of the mediastinal lymphadenopathy was 1.53 mm with FDG-PET versus 10.2 mm for CT alone (p= 0.0005), resulting in a 6.7 fold reduction in interobserver variability. Median Dice Similarity Coefficient (DSC) for the primary GTV contours was 0.87 for FDG-PET/CT and 0.74 for CT alone. For the nodal GTV DSC were 0.79 and 0.59, respectively. Physician agreement on the number of lymph nodes contoured was 15/29 on CT and 27/29 patients for FDG-PET/CT. Only two of the three physicians agreed on the number of lymph nodes contoured for CT alone in 12/29 versus only 2/29 patients for FDG-PET/CT (p=0.0018).

      Conclusion
      FDG-PET/CT significantly reduces mean lung tumor and mediastinal nodal GTV, is more precise for size and position in defining target volumes, and reduces interobserver variability. There was greater agreement for the number of lymph nodes contoured on FDG-PET/CT compared to CT alone.

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    P2.24 - Poster Session 2 - Supportive Care (ID 157)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Supportive Care
    • Presentations: 1
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      P2.24-023 - A descriptive pilot study to evaluate the current practices of determining "Do Not Resuscitate Status" in patients with incurable lung cancer at Cancer Care Manitoba, Canada. (ID 1570)

      09:30 - 09:30  |  Author(s): N. Ahmed

      • Abstract

      Background
      At Cancer Care Manitoba (CCMB), Canada, lung cancer patients when considered incurable, are often enrolled into the palliative care program. One of the most important pre-requisites for patients to enroll into this program is to have a Do Not Resuscitate (DNR) status determined and signed by an authorized cancer care provider.Currently there are no guidelines on how and when to address advanced care planning and more specifically when to discuss DNR status. At this time the issue appears to be addressed on an individual basis depending on the patient’s unique circumstances and the personal practice of the physician involved. DNR discussions in the context of incurable lung cancer can be difficult for a number of reasons that include but are not limited to: social or family complexities such as dysfunctional dynamics or conflicted goals for medical attention, cultural differences, limited patient and/or family understanding of the patient’s prognosis, a recent diagnosis, limited time for discussion, physician preferences, and questionable patient cognitive competence secondary to pain, medications, brain metastases, whole brain radiotherapy, and emotional stress caused by the disclosure of incurable nature of the disease . Lung cancer team at CCMB has identified a need to explore the current practice and opinions around DNR discussion and future development of advance care planning guidelines. The findings from the current pilot study may serve the basis for a prospective randomized trial that tests an intervention that incorporates the timing of DNR discussions.

      Methods
      From January 2012 to November 2012 a total of 10 lung cancer patients who had previously discussed and determined their DNR status, 9 family members, and 10 health care providers were identified and agreed to participate. A mixed quantitative and qualitative methodology including a written questionnaire followed by a nurse directed audio recorded interview was employed to determine participant’s views. Interviews were transcribed and then content analysis and constant comparison techniques were used to identify, code, and categorize primary patterns in the collected data.

      Results
      Major themes identified from the patient and caregiver’s perspective include their trust in the health care system, the need for clear communication, the desire to be respected, and the benefit of having family present during discussion. Health care provider’s commonly expressed the importance of having adequate clinic time for discussions and the need for the process to be adaptable. Admission into a palliative care program is the most common trigger for initiating discussions but other points earlier in the disease course may also be appropriate. The presumed level of stress that patients are thought to undergo with DNR discussions is less than they actually report. Fnal data analysis is pending and subject to refinement before final presentation.

      Conclusion
      DNR status decision-making is a complex process, influenced by patient, family, and health care provider factors. The implementation of a standard approach to DNR discussions could potentially be restrictive. Potential areas of improvement include additional resources, and the specific guidelines. A need for a prospective trial addressing the timing of DNR discussion was identified but may not be feasible.