Patterns, causes, and clinical impact of treatment interruption on early outcomes in patients receiving radiotherapy for lung cancer: a retrospective study.

BACKGROUND: Radiation therapy is key for lung cancer, but data on unplanned interruptions remains limited. OBJECTIVES: This study investigated patterns, risk factors, and clinical impacts of radiotherapy interruptions in lung cancer patients. METHODS: A retrospective study enrolled 230 lung cancer patients undergoing radiotherapy (Jan 2020-Dec 2022). After exclusion, 226 patients were analyzed and stratified into interrupted and non-interrupted groups by unplanned radiotherapy interruptions (≥1-day pause, excluding scheduled breaks). Patterns and causes of interruptions were documented in detail. Early oncological response, treatment completion, acute toxicities, progression-free survival (PFS), and overall survival (OS) were monitored at 6 months post-radiotherapy. Multivariable linear regression identified interruption risk factors, while Cox regression and Kaplan-Meier analysis with log-rank test evaluated survival. RESULTS: A total of 226 lung cancer patients were enrolled, 79 (34.96%) of whom had at least one treatment interruption, with a median duration of 5 days and 1 episode. Most interruptions occurred in the middle third of radiotherapy (60.76%), mainly caused by treatment-related toxicities (49.37%) and patient-related factors (27.85%). Multivariable linear regression showed that performance status (PS) score 2-3, stage III-IV and tumor volume ≥50 cm³ remained significantly associated with radiotherapy interruption after adjustment for potential confounders (all P<0.05). The interrupted group had poorer compliance, lower overall response rate (ORR) and disease control rate (DCR), higher acute toxicities. Unadjusted Kaplan-Meier analysis showed worse 6-month PFS and OS in the interrupted group, and this association persisted in multivariable-adjusted Cox regression after controlling for PS score, tumor stage, tumor volume, treatment regimen, and radiotherapy modality (all P < 0.001). CONCLUSIONS: Radiotherapy interruption is common in lung cancer patients, mainly caused by toxicity. It impairs treatment efficacy and survival, requiring individualized management.