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The impact of intra-thoracic anatomical changes upon the delivery of lung stereotactic ablative radiotherapy
Brown, S. Beasley, M. Chuter, R. Faivre-Finn, Corinne Franks, K. Henry, A. Murray, L. van Herk, Marcel
Brown, S.
Beasley, M.
Chuter, R.
Faivre-Finn, Corinne
Franks, K.
Henry, A.
Murray, L.
van Herk, Marcel
Citations
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Abstract
Introduction: Current evidence demonstrates that 72% of lung
patients undergoing curative radiotherapy develop intra-thoracic
anatomical changes (ITACs). However, only 12% of these are
significant enough to alter treatment dosimetry. The impact of
ITACs on patients receiving stereotactic ablative radiotherapy (SABR) for lung cancer, however, is unknown. The aim of this study is to
describe the occurrence of ITACs on cone-beam CT (CBCT) imaging
and the impact in lung cancer patients treated with SABR.
Methods: 100 patients treated with SABR for early non-small
cell lung cancer at The Christie Hospital and Leeds Cancer Centre
were identified. CBCTs (acquired at every treatment fraction)
were reviewed for the presence of the following ITACs: atelectasis,
infiltrative change, pleural effusion, baseline shift, gross tumour
volume (GTV) increase and GTV decrease. These were graded using
a traffic light protocol (developed by Kwint et al., 2014) to assess
the potential for target under-coverage. The frequency of physics or
clinician requests to review the impact of ITACs was also recorded.
Results: Results are shown in Fig. 1. The majority of CBCTs
demonstrated no ITACs (85%). However, 18% of ITACs were graded
as 'red', implying a potential risk of target under-coverage due to
the impact upon the planning target volume (PTV). Most (49%)
were 'yellow' with minimal impact upon PTV coverage of the
target. Physics or clinician review was required for 9% of treatment
fractions. Three patients needed to have their treatment replanned Conclusion: ITACs were observed in 23% of patients undergoing
SABR for lung cancer at two independent UK centres. The majority
are minor; however, they are associated with unplanned physics
or clinician review in 9% of treatments and therefore represent a
resource burden. There is a need to incorporate detailed guidance on
the management of ITACs into IGRT workflows. This would improve
radiographer confidence in treating these patients.
Description
Date
2019
Publisher
Collections
Keywords
Type
Meetings and Proceedings
Citation
Brown S, Beasley M, Chuter R, Faivre-Finn C, Franks K, Henry A, et al. The impact of intra-thoracic anatomical changes upon the delivery of lung stereotactic ablative radiotherapy. Lung Cancer. 2019;127:S74-S5.