Author of

• 14782

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  ORAL 19 - Radiation for Localized Lung Cancer (ID 126)

  • Event: WCLC 2015
  • Type: Oral Session
  • Track: Treatment of Localized Disease - NSCLC
  • Presentations: 1
  • Moderators:D. De Ruysscher, M. Hiraoka
  • Coordinates: 9/08/2015, 10:45 - 12:15, 102+104+106

  • 14788

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    ORAL19.06 - Tumor Location Is Associated with Recurrence Pattern and Survival after SBRT in Early Stage NSCLC Patients (ID 2623)

    11:39 - 11:50  |  Author(s): N. O'Connell
    • Abstract
    • Slides

    Background:
    For NSCLC patients treated with SBRT, we investigated if tumor location is associated with recurrence pattern and overall survival.
    
    Methods:
    From 2006-2013 1129 patients with early stage NSCLC were treated with cone beam CT guided SBRT (median 54 Gy in 3 fractions, range 23-64 Gy in 1-10 fractions) in 5 different institutes. 719 patients were analyzed after exclusion of patients with (meta)synchronous tumors (n=185), incomplete scanning data or incomplete follow-up (n=225). An average anatomy was constructed based on 109 patients of the 5 institutes using deformable image registration[1]. Subsequently, all patients were registered to this average anatomy and the corresponding dose distribution was deformed accordingly. Tumor location was defined as a 3D Gaussian distribution (standard deviation 2 cm) at the center of the high dose region. These Gaussian distributions were added to a total and per voxel a mean and standard deviation was determined. Totals were obtained for 5 different groups: local recurrence, regional recurrence, distant metastasis, all recurrent disease combined, deceased as well as their complements. By comparing 2 complimentary groups using Welch’s t-test, locations that were significantly associated (p<0.01) with recurrent disease or with overall survival were identified. Recurrent disease rates and overall survival were calculated using the Kaplan-Meier method.
    
    Results:
    With a median follow-up of 19 months, local recurrence occurred in 5% of patients, regional recurrence in 5% and distant metastasis in 9%. 74% of patients were alive and 18% was lost to follow-up. Tumors located medially in the left upper lobe were significantly associated with controlled disease (local, regional, distant and all combined). Figure 1A displays as heatmap: disease control (green), recurrent disease (purple), and the region where the two groups differ significantly (yellow). Tumors located peripherally in the left lower lobe were significantly associated with regional recurrences. Tumors located medially/centrally in the right upper lobe were significantly associated with distant metastases and all recurrent disease combined (local, regional and distant together). Tumors located medially/centrally in the right upper lobe were significantly associated with a decreased overall survival (Figure 1B). Figure 1
    
    
    
    Conclusion:
    In this group of 719 NSCLC patients treated with SBRT, an average anatomy was utilized to analyze associations of tumor location with treatment outcome. Several regions were identified that were significantly associated with disease recurrence and overall survival. Further investigations in the underlying mechanisms of these associations are warrented. 1.ADMIRE Research 2015, Elekta AB, Stockholm, Sweden
    
    

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