WCLC 2025 - Posters & ePosters-P2.08 .19 Proton Beam Therapy for Lung Cancer in Patients With Interstitial Lung Disease: Initial Experience From the United Kingdom

P2.08 .19 Proton Beam Therapy for Lung Cancer in Patients With Interstitial Lung Disease: Initial Experience From the United Kingdom

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This study presents the initial United Kingdom experience of proton beam therapy (PBT) for treating lung cancer in patients with interstitial lung disease (ILD), a population at high risk of severe treatment-related toxicities, especially radiation pneumonitis. Four patients with lung cancer and ILD, all former smokers with varying ILD subtypes, were treated with 60 Gy in 30 fractions using 2-field Single Field Optimization PBT plans. Planning incorporated strategies to account for respiratory motion and robust optimization to ensure target coverage and organ-at-risk (OAR) sparing, particularly minimizing dose to healthy lung tissue.<br /><br />Dosimetric results demonstrated successful fulfillment of target coverage and OAR dose constraints, with median lung V20Gy at 19.8%—lower than typical photon-based radiotherapy—and mean doses to lung and heart within safe limits. This dose distribution was attributed to the physical advantages of protons, including the Bragg Peak, permitting superior sparing of normal lung tissue while maintaining tumor coverage. Acute toxicity assessments, conducted weekly during treatment and one week after, identified only mild to moderate side effects (grade 1-2), with no severe (grade 3 or above) toxicities reported. Fatigue, shortness of breath, cough, skin reactions, and dyspepsia were noted but manageable.<br /><br />The findings are promising, indicating that PBT can be safely delivered in this high-risk population without compromising efficacy or causing excessive toxicity. The reduced lung dose is critical in patients with ILD, as their compromised lung function makes them especially vulnerable to radiation pneumonitis and other complications. With the recent establishment of two PBT centers in the UK, ongoing long-term surveillance is necessary to evaluate late toxicities, disease control, and survival to better define PBT's role and optimize treatment protocols for lung cancer patients with ILD. Overall, this study supports further exploration and potential wider adoption of PBT to address the therapeutic challenges presented by lung cancer coexisting with ILD.

Asset Subtitle

Caroline Maguire

Meta Tag

Speaker Caroline Maguire

Topic Local-Regional Non-small Cell Lung Cancer

Keywords

proton beam therapy

lung cancer

interstitial lung disease

radiation pneumonitis

dosimetric results

Bragg Peak

organ-at-risk sparing

treatment toxicity

UK proton therapy centers

respiratory motion management