Main Session
Sep
28
PQA 02 - Lung Cancer/Thoracic Malignancies, Patient Reported Outcomes/QoL/Survivorship, Pediatric Cancer
2460 - Balancing Quality of Life Considerations and Efficacy of Stereotactic Body Radiotherapy in Patients with Interstitial Lung Disease
Presenter(s)
Simran Polce, MD - Moffitt Cancer Center, Tampa, FL
S. A. Polce1, A. Gan2, V. Arteaga3, S. M. Naqvi4, K. Latifi5, J. Kim1, T. J. Dilling1, and S. A. Rosenberg1; 1H. Lee Moffitt Cancer Center and Research Institute, Department of Radiation Oncology, Tampa, FL, 2University of South Florida Morsani College of Medicine, Tampa, FL, 3Moffitt Cancer Center, Tampa, FL, 4Biostatistics and bioinformatics, Moffitt Cancer Center, Tampa, FL, 5H. Lee Moffitt Cancer Center and Research Institute, Department of Medical Physics, Tampa, FL
Purpose/Objective(s):
Stereotactic Body Radiotherapy (SBRT) for Non-Small Cell Lung Cancer (NSCLC) is generally well tolerated. Patients with Interstitial Lung Disease (ILD) who undergo SBRT for NSCLC face a significant risk of disease exacerbation, which not only leads to high morbidity (50%) and mortality (33%) but also severely diminishes their quality of life (QOL) due to progressive respiratory decline, increased dependence on supplemental oxygen, and recurrent hospitalizations. Studies report high rates of ILD exacerbations following SBRT, further complicating treatment outcomes and underscoring the need for strategies to mitigate toxicity while preserving lung function and overall well-being. A recent trial of 39 ILD patients treated with SBRT showed a 7.7% treatment related mortality rate. Proposed dose limits to reduce toxicity are Lung V20 <6.5% and MLD <450cGy (Chen et al.). We hypothesize these limits predict for fewer respiratory adverse events (AEs), and that pre-treatment steroids, extended fractionation, or QOD treatment may reduce toxicity while preserving QOL.Materials/Methods:
A retrospective review (Jan 2019–Aug 2024) identified ILD patients with NSCLC treated with SBRT (50-70Gy/5-10Fx) on consecutive (CD) or alternating days (QOD). Steroid pre-treatment was 4mg dexamethasone on RT days. ILD was confirmed by a blinded radiologist. Variables analyzed included patient characteristics, ILD type, Lung V20, and MLD. Univariate analyses used t-tests and chi-square tests; Cox models assessed PFS.Results:
30 patients (23 men, avg. age 77, range 59-93) with a 47.1 pack-year smoking history (range 0-114) were reviewed. Treatment regimens: CD without steroids (n=18), QOD with steroids (n=9), CD with steroids (n=2), and QOD without steroids (n=1). ILD etiologies: autoimmune (n=4), environmental (n=6), and idiopathic pulmonary fibrosis (n=20). IGTV mean 25.03cc (range 3.7-89.1), PTV mean 53.89cc (range 10.5-154.3). Mean Lung V20 was 4.79% (range 0.97-17.4), MLD 373cGy (range 80-893.6). Median follow-up: 26 months (95% CI 12.7-42.9). Eight patients had respiratory AEs: three ILD flares (mean 7.67 months post-Tx) and five ILD progressions (mean 10 months post-Tx). All ILD progressions occurred in CD Tx patients (p=0.035). Steroids did not correlate with AEs (p=0.673). V20<6.5% and MLD <450cGy did not predict lower respiratory AEs (p=0.91 and 0.76, respectively). One case of fatal radiation pneumonitis complicated by sepsis occurred 35 days post-Tx. Eight additional deaths were attributed to non-Tx or non-ILD causes (mean 18.1 months post-Tx). PFS was 18.5 months (8 failures).Conclusion:
SBRT was tolerated in ILD patients with NSCLC, with fewer grade 5 toxicities than recent prospective data. QOD Tx correlated to decreased incidence of respiratory AEs which may improve QOL, while steroids were not correlated with incidence of respiratory AEs. No correlation was found between proposed dose limits and AEs. Further prospective studies are needed to optimize RT for ILD patients.