2358 - Treatment Interruptions in NSCLC Radiotherapy: Impact on Outcomes in a Statewide Quality Collaborative
Presenter(s)
A. L. Elaimy1, L. Higgins1, M. Schipper2, H. Yin3, M. M. Matuszak1, M. M. Dominello4, D. P. Bergsma1, P. A. Paximadis5, M. Zaki6, L. L. Kestin7, J. A. Hayman2, A. F. Dragovic1, and S. Jolly1; 1Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, 2University of Michigan, Ann Arbor, MI, 3Department of Biostatistics, University of Michigan, Ann Arbor, MI, 4Department of Radiation Oncology, Karmanos Cancer Center, Detroit, MI, 5Department of Radiation Oncology, Corewell Health South, St. Joseph, MI, 6Covenant HealthCare, Saginaw, MI, 7Michigan Healthcare Professionals/GenesisCare USA, Farmington Hills, MI
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 Kaplan-Meier 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.