Incidence of new-onset atrial fibrillation after thoracic radiotherapy in non-small cell lung cancer: a systematic review and meta-analysis

Background Atrial fibrillation (AF) may represent an important component of cardiac toxicity after thoracic radiotherapy in patients with non-small cell lung cancer (NSCLC). However, the available evidence remains limited and heterogeneous. Methods We conducted a systematic review and meta-analysis of observational studies evaluating AF after thoracic radiotherapy in NSCLC. PubMed, Scopus, Web of Science, Embase, and Cochrane Central were searched from inception to March 2026. The primary outcome was pooled new-onset AF. A separate exploratory analysis evaluated cumulative incidence of AF at reported follow-up intervals using random-effects models. Results Nine retrospective cohort studies were included in the systematic review, and eight were eligible for quantitative synthesis. Six of the eight studies contributed to the primary analysis, whereas two did not report the primary outcome in a directly comparable format, including 4410 patients and 736 events. The pooled proportion of new-onset AF was 0.14 (95%CI 0.07–0.24), with substantial heterogeneity (I2 = 94.0%). Three studies contributed to the cumulative-incidence analysis, although the pooled estimate was highly imprecise (0.09, 95% CI, 0.00–0.84; I2 = 0.0%). Across studies, AF risk appeared to be associated with radiation exposure to cardiac substructures, particularly the sinoatrial node, pulmonary veins, and atrial structures. Conclusion AF may represent a clinically relevant component of cardiac toxicity after thoracic radiotherapy in NSCLC, but the current evidence remains limited by retrospective study design and marked heterogeneity, underscoring the need for prospective validation and standardized outcome reporting.