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J. De Bois



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    O14 - Radiotherapy - Toxicity and Clinical Trials (ID 105)

    • Event: WCLC 2013
    • Type: Oral Abstract Session
    • Track: Radiation Oncology + Radiotherapy
    • Presentations: 1
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      O14.02 - Vertebral fractures in NSCLC patients treated with IMRT and concurrent chemotherapy (ID 1880)

      10:30 - 12:00  |  Author(s): J. De Bois

      • Abstract
      • Presentation
      • Slides

      Background
      Purpose To report on the incidence of vertebral fractures in locally advanced NSCLC patients treated with intensity modulated radiation therapy (IMRT) and concurrent chemotherapy. The RT dose to the vertebra was analyzed for its association with fractures.

      Methods
      Methods A total of 524 patients were treated between 2007 and 2011, with hypofractionated IMRT (66Gy/24fx) and concurrent daily low dose cisplatin. Planning and follow-up CT or MRI scans were retrospectively utilized to identify vertebral collapse by an experienced radiologist and a technician. Clinical and dosimetric parameters were retrospectively collected. Patients were excluded if they had no follow-up CT/MRI scan; had prior irradiation for thoracic or head and neck cancer; showed a vertebral fracture in the planning CT; or had vertebral collapse due to other causes. First, we reported the incidence of vertebral fractures. Afterwards, we analyzed the RT dose effect relationship using the maximum (Dmax) and mean (Dmean) dose to each vertebra. Dose-response was modeled using Cox model with patient as random effect. Data were analyzed using R, package “coxme”.

      Results
      Results Three hundred and thirty six patients were eligible for analysis. The median follow-up was 24 months The median age was 64 years (range 32-87); 40% of the patients female and 94% had a performance score (PS) 0-1. Twenty-eight (8%) patients developed ≥ 1 vertebral fracture; 22 had 1 vertebral fracture, 5 had 2 and 1 patient had 3 vertebral fractures. All fractures were located from the 6[th]-8[th] thoracic vertebra.The median onset time for the fracture was 7 months (range 2-26). The median age for the 28 fractured patients was 70 years (range 42-82); 61% were female, 89% had a PS of 0-1. The median Dmax was 40Gy (range 0-83) and 72Gy (range 42-83) for non-collapsed and fractured vertebrae, respectively. The median Dmean was 12Gy (range 0-65) and 51Gy (range 18-71) for non-collapsed and collapsed vertebras, respectively. Both Dmax and Dmean were significantly (p<0.001) associated with vertebral fractures.

      Conclusion
      Conclusion Vertebral fractures were retrospectively identified in 8% of NSCLC patients treated with IMRT and concurrent chemotherapy. The median onset time was 7 months. Both Dmax and Dmean of the vertebra were significantly associated with collapse in the collapsed population. A case-control study is in progress to analyze the dose-response relationship in the entire population and incorporate clinical variables, such as age, performance status and menopause status.

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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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      P2.08-020 - Prognositc parameters for local and regional control in locally advanced NSCLC patients treated with concurrent chemo-radiotherapy (ID 2385)

      09:30 - 16:30  |  Author(s): J. De Bois

      • Abstract

      Background
      Traditionally, the same radiotherapy dose is prescribed to the primary tumor (PT) and involved lymph nodes (LN) for locally advanced NSCLC patients, independent of volume and metabolic activity of each lesion. On the other hand, the PT and lesions with a high [18]F-FDG uptake are often believed to have a higher recurrence rate. The purpose of this study was therefore to find prognostic parameters for the lesion control probability in locally advanced NSCLC.

      Methods
      A total of 279 patients treated between 2007 and 2011 with 24×2.75Gy IMRT and concurrent daily low dose cisplatin were included in this retrospective analysis. Patients had a staging FDG-PET scan within 6 weeks prior the start of treatment. For follow-up, CT thorax was performed 4-6 weeks after treatment and at 3-monthly intervals chest x-ray or CT scans were made up to 2 years after CCRT. Medical records of the patients were retrospectively reviewed. The PT and/or LN progression were classified based on follow-up records and scans by two physicians. The volume of each separate lesion on the planning CT and their SUVmax from the pre-RT staging PET scan were then tested as prognostic factors for disease progression using Cox proportional hazard model with patient as random effect. Data were analyzed using R, package “coxme”.

      Results
      A total of 291 PTs (8 patients had no PT, 252 had 1 PT, 18 had 2 PTs, 1 had 3 PTs) and 627 LNs (59 patients without LN, 57 had 1 LN, 57 had 2 LNs and 106 had >=3 LNs involved) were analyzed. The majority (92%) of the patients had TNM stage III and 86% patients had ≥N2. At a median follow-up of 30 months (95%CI 27-35) and median OS of 25 months (95% CI 21-29), 47 PTs had progression and 14 LNs had progression, 38% patients had systemic relapse. The log(Vol), SUVmax and lesion type (TP vs. LN) were each significant (p<0.001) as prognostic factor for progression in the univariate cox regression. In the multivariate analysis, log(Vol) remains as a significant predictor (p<0.001) with a trend toward significance for lesion type (p=0.07) (Figure 1). Figure 1

      Conclusion
      Our regimen of 66 Gy in 24fx results in excellent local-regional control in locally advanced NSCLC patients. The PT yields a significantly higher risk of progression than LNs. A larger lesion volume and higher SUVmax were associated with an increased risk of progression.