Adding Ipsilateral V{sub 20} and V{sub 30} to Conventional Dosimetric Constraints Predicts Radiation Pneumonitis in Stage IIIA-B NSCLC Treated With Combined-Modality Therapy
- Radiotherapy Unit, Campus Bio-Medico University, Rome (Italy)
- Department of Thoracic Surgery, Tor Vergata University, Rome (Italy)
- Department of Radiation Therapy, Catholic University, Rome (Italy)
- Department of Physics, Catholic University, Rome (Italy)
- Lung Cancer Unit, National Cancer Research Institute, Genoa (Italy)
- Clinical CdC San Raffaele, Velletri (Italy)
Purpose: To determine lung dosimetric constraints that correlate with radiation pneumonitis in non-small-cell lung cancer patients treated with three-dimensional radiation therapy and concurrent chemotherapy. Methods and Materials: Between June 2002 and December 2006, 97 patients with locally advanced non-small-cell lung cancer were treated with concomitant radiochemotherapy. All patients underwent complete three-dimensional treatment planning (including dose-volume histograms), and patients were treated only if the percentage of total lung volume exceeding 20 Gy (V{sub 20}) and 30 Gy (V{sub 30}), and mean lung dose (MLD) had not exceeded the constraints of 31%, 18%, and 20 Gy, respectively. The total and ipsilateral lung dose-volume histogram parameters, planning target volume, and total dose delivered were analyzed and correlated with pneumonitis incidence. Results: If dose constraints to the total lung were respected, the most statistically significant factors predicting pneumonitis were the percentage of ipsilateral lung volume exceeding 20 Gy (V{sub 20}ipsi), percentage of ipsilateral lung volume exceeding 30 Gy (V{sub 30}ipsi), and planning target volume. These parameters divided the patients into low- and high-risk groups: if V{sub 20}ipsi was 52% or lower, the risk of pneumonitis was 9%, and if V{sub 20}ipsi was greater than 52%, the risk of pneumonitis was 46%; if V{sub 30}ipsi was 39% or lower, the risk of pneumonitis was 8%, and if V{sub 30}ipsi was greater than 39%, the risk of pneumonitis was 38%. Actuarial curves of the development of pneumonitis of Grade 2 or higher stratified by V{sub 20}ipsi and V{sub 30}ipsi were created. Conclusions: The correlation between pneumonitis and dosimetric constraints has been validated. Adding V{sub 20}ipsi and V{sub 30}ipsi to the classical total lung constraints could reduce pulmonary toxicity in concurrent chemoradiation treatment. V{sub 20}ipsi and V{sub 30}ipsi are important if the V{sub 20} to the total lung, V{sub 30} to the total lung, and mean lung dose have not exceeded the constraints of 31%, 18%, and 20 Gy, respectively.
- OSTI ID:
- 21367593
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 76, Issue 1; Other Information: DOI: 10.1016/j.ijrobp.2009.01.036; PII: S0360-3016(09)00132-1; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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