Author of

• 11645

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

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Radiation Oncology + Radiotherapy
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 11670

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    P2.08-025 - A study of respiratory-induced tumour motion based on anatomical lung location using 4DCT in lung cancer patients (ID 2976)

    09:30 - 09:30  |  Author(s): N. Hardcastle
    • Abstract

    Background
    Respiratory induced tumour motion is one of several challenges encountered when delivering radical radiotherapy to lung cancer patients. In recent years, four-dimensional computed tomography (4DCT) has improved our ability to accurately define lung tumour motion during breathing. Using 4DCT images, our study aims to compare the magnitude of lung tumour motion due to respiration, amongst different anatomical lobes and pulmonary zones. This may help guide personalised radiotherapy margins for patients with lung cancer.

    Methods
    This is a retrospective study of 100 consecutive patients from the Peter MacCallum Cancer Centre treated with curative intent radiotherapy for lung cancer. All 4DCT scans accessible from patients scanned between December 2009 and May 2013 were included. Images were analysed using the MIM v5.6 software. Tumour volumes were delineated by a single observer and propagated to include all 10 phases of the respiratory cycle. Movements were tracked in the superior-inferior (SI), anterior-posterior (AP) and medio-lateral (ML) directions by changes in the gross tumour volume centroid coordinates. Tumour motion characteristics were correlated with anatomical lobe, pulmonary zone, tumour volume, histopathology, spirometry and T-stage. Tumours with chest wall or mediastinal invasion were excluded. Statistical analyses were performed using Prism v6.0.

    Results
    Preliminary data from 82 patients showed the greatest mean movement in the SI direction among lower lobe tumours compared to those located in the upper lobes [Left lower, 8.0mm, n = 13, vs. Left upper, 1.3mm, n = 24] [Right lower, 6.4mm, n = 19, vs Right upper, 1.9mm, n = 28], p < 0.01. In all lobes, mean movements were similar in the AP [1.6mm, Right lower; 2.1mm, Right middle; 1.8mm, Right upper; 2.3mm, Left lower; 1.6mm, Left upper] and lateral directions [0.9mm, Right lower; 2.4mm, Right middle; 1.2mm, Right upper; 1.5mm, Left lower; 1.2mm, Left upper]. 35 patients were staged as T1, 30 as T2 and 14 as T3. Mean lung tumour motion decreased with increasing T stage in the SI direction [3.9mm, T1; 3.7mm, T2; 3.5mm, T3], however this was not statistically significant. Assessment of the association between tumour motion and spirometry findings is ongoing. Figure 1

    Conclusion
    The degree of lung tumour motion varies widely according to its position within the lung. The largest differences in tumour motion was between the upper and lower lobes in the SI direction. Analysis of all 100 patient datasets is ongoing.