Influencing Factors of Low-Dose Computed Tomography Screening Behavior among First-Degree Relatives of Lung Cancer Patients Based on the Theory of Planned Behavior: a Qualitative Study

ObjectiveTo explore the factors influencing the screening behavior of first-degree relatives of lung cancer patients toward low-dose computed tomography (LDCT) screening based on the Theory of Planned Behavior (TPB), gain deeper insights into their subjective experiences and core demands, and provide a theoretical basis and improvement measures for enhancing screening participation rates among this high-risk population.MethodsEmploying a descriptive phenomenological approach, semi-structured interviews were conducted with 14 first-degree relatives of lung cancer patients at a hospital from May to July 2025. Thematic analysis was performed using directed content analysis.ResultsGuided by the TPB, 11 themes across 3 dimensions were identified: Behavioral Attitudes (affirming screening value, family environment influence, cognitive biases hindering screening), Subjective Norms (influence of others’ behavior, healthcare professional recommendations, rural cognitive limitations), and Perceived Behavioral Control (financial constraints, work-time conflicts, cumbersome screening procedures, negative psychological perceptions, policy reference effects).ConclusionScreening behaviors among first-degree relatives of lung cancer patients are influenced by multidimensional factors. Healthcare providers should integrate the TPB framework and implement multi-level improvement measures—including enhanced health education, optimized screening services, and improved policy support—to increase screening adherence.