TITLE:
Comparison of Stereotactic Body Radiotherapy Delivery Techniques for Early-Stage Lung Cancer Using Lung Toxicity Modeling
AUTHORS:
Chunhui Han, Timothy E. Schultheiss, Jeffrey Y. C. Wong
KEYWORDS:
Early-Stage Lung Cancer, SBRT, Stereotactic Body Radiotherapy, Lung Toxicity
JOURNAL NAME:
International Journal of Medical Physics, Clinical Engineering and Radiation Oncology,
Vol.7 No.1,
January
24,
2018
ABSTRACT: Purpose: Lung
toxicity is a primary side effect in stereotactic radiotherapy (SBRT) for
early-stage non-small cell lung cancer (NSCLC). We aimed to use a set of
radiobiological models to evaluate and compare modern IMRT delivery techniques
with three-dimensional conformal techniques for SBRT treatment of NSCLC in
terms of lung toxicity, and aimed to compare the results from different
radiobiologcal models. Methods: Ten early-stage NSCLC patients treated
with SBRT were retrospectively selected. Five treatment plans were generated to
deliver 50 Gy in five fractions to the planning target volume for each case: a
helical tomotherapy (HT) plan, two three-dimensional cofnromal radiotherapy
(3D-CRT) plans using 6-MV and 10-MV photon beams respectively, and two
volumetric modulated arc therapy (VMAT) plans using one and two arc fields
respectively. The lung RDV was calculated with three parallel functional
sub-unit (FSU) models and two normal tissue complication probability (NTCP)
models. Results: Both the HT and VMAT plans showed significantly higher
contralateral mean lung dose and lower ipsilateral mean lung dose compared to
the 3D-CRT plans. There was no statistically significant difference in terms of
lung toxicities between the IMRT and 3D-CRT techniques using either the FSU
models or the NTCP models. Based on both the FSU and the NTCP models, there was
strong correlation between lung toxicity and the mean lung dose in SBRT
treatment plans. Conclusions: Based on both the NTCP and parallel FSU
models, both IMRT and traditional 3D-CRT delivery techniques could achieve
comparable lung sparing inn SBRT treatment of early-stage lung cancer. However,
the validity of the radiobiological model results should be checked by clinical
data.