Financial toxicity among patients with lung cancer: a systematic review and meta-analysis.

Lung cancer imposes a substantial global health burden. Although advances in treatment have improved outcomes, increasingly prolonged and complex care may impose considerable financial pressure on patients and their families. We systematically synthesized evidence on financial toxicity (FT) and its associated factors among patients with lung cancer. PubMed, Embase, the Cochrane Library, and Scopus were systematically searched through November 2025 for observational studies evaluating FT in patients with lung cancer. Associated factors were synthesized qualitatively and mapped using a harvest plot. Random-effects models were used to pool study-specific FT proportions and mean COST-based scores. Exploratory subgroup analyses were conducted by country income level, disease stage/treatment setting, and COST-based FT threshold. Heterogeneity was assessed using Cochran's Q and I² statistics. Prediction intervals and leave-one-out analyses were used to evaluate variability and robustness. Eighteen studies were included. The pooled proportion of patients meeting study-specific FT definitions across eight studies was 0.55 (95% CI, 0.43-0.66), while the pooled mean COST-based score across ten studies was 22.91 (95% CI, 20.57-25.25). The pooled FT proportion was numerically lower in high-income than in upper-middle-income countries (0.47 vs 0.61; p = 0.171). FT proportions differed by disease stage/treatment setting (advanced/systemic treatment, 0.50; mixed/all-stage populations, 0.67; surgery-dominant populations, 0.42; p = 0.031). No difference was observed between studies using COST-based thresholds of 21-22 and 23-25 (p = 0.999). Lower income, inadequate insurance protection, employment disruption, limited savings, and greater out-of-pocket burden were recurring correlates of worse FT. Substantial heterogeneity persisted across analyses. FT represents an important but highly context-dependent burden among patients with lung cancer. Given the substantial heterogeneity and predominantly cross-sectional evidence, the pooled estimates should be interpreted as exploratory summaries rather than universally applicable benchmarks. Standardized longitudinal assessment and prospective evaluation of risk-stratified interventions are warranted.