Treatment Interruptions in NSCLC Radiotherapy: Impact on Outcomes in a Statewide Quality Collaborative

Document Type

Conference Proceeding

Publication Date

9-2025

Publication Title

International Journal of Radiation Oncology, Biology, Physics

Abstract

Purpose/Objective(s): For patients receiving radiation therapy for non-small cell lung cancer (NSCLC), unplanned interruptions prolong the treatment course. However, little is known regarding patient and treatment planning characteristics that contribute to interruptions as well as the consequences of these interruptions on clinical outcomes. The purpose of this study was to characterize the frequency, predictors, and prognosis of patients with NSCLC who experienced interruptions in radiation therapy throughout a statewide quality collaborative. Materials/Methods: Clinical and dosimetric data as well as frequency and duration of treatment interruptions (> or ≤ 5 days), were prospectively collected by 29 institutions within the Michigan Radiation Oncology Quality Consortium between 2017 and 2024 for patients with NSCLC treated with conventional fractionation and systemic therapy at the discretion of the medical team using a physician-assessed survey. We modeled the influence of patient, disease, and treatment characteristics including radiation dose metrics for lung and esophagus on the odds of any treatment interruption, toxicity breaks, and toxicity breaks > 5 days using multivariate logistic regression. We also assessed the potential effect of any treatment interruption on locoregional progression free survival (LR-PFS) using KaplanMeier survival estimates. Results: Any treatment interruption was reported in 20% of patients (189/ 963), toxicity breaks were reported in 6% of patients (59/963), and prolonged toxicity breaks (>5 days) were reported in 2% (20/963). Multivariate analysis identified key predictors of toxicity-related breaks: comorbidity group (1 vs. 3, OR = 0.397; 95% CI 0.173-0.910), planning target volume (PTV) (OR = 1.001; 95% CI 1.001-1.002), and maximum esophageal dose (DMax) (OR = 1.07; 95% CI 1.011-1.132). Predictors of prolonged toxicity breaks (>5 days) included lung V5 (OR = 1.065; 95% CI 1.031-1.100) and patient age (OR = 1.070; 95% CI 1.014-1.128). Any treatment interruption was associated with worse locoregional progression-free survival (20- month LR-PFS, 44% vs 59%) (HR = 1.518; p = 0.0032). Conclusion: These findings underscore the potential impact of treatment interruptions on clinical outcomes in NSCLC patients receiving conventionally fractionated radiation. Identifying high-risk patients based on clinical and dosimetric factors is crucial for optimizing treatment planning and reducing interruptions. Targeted interventions to mitigate these risks could improve treatment continuity and ultimately improve patient outcomes.

Volume

123

Issue

1 Suppl

First Page

e156

Last Page

e156

Comments

ASTRO 2025, 67th Annual Meeting American Society for Radiation Oncology, September 27 - October 1, 2025, San Francisco, CA

DOI

10.1016/j.ijrobp.2025.06.3637

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