Risk of venous thromboembolism in lung cancer patients treated with chemotherapy versus immunotherapy: A propensity-matched TriNetX analysis.

Abstract

e20070 Background: Venous thromboembolism (VTE) is a major cause of morbidity and mortality in patients with lung cancer. While immunotherapy has transformed lung cancer treatment, its association with thrombotic risk compared with conventional chemotherapy remains incompletely characterized. Methods: We conducted a retrospective cohort study using the TriNetX research network. Adult patients with lung cancer receiving either chemotherapy or immune checkpoint inhibitor–based immunotherapy were identified. The primary outcome was incident venous thromboembolism after treatment initiation. Cohorts were balanced using 1:1 propensity score matching based on demographics and clinical characteristics. Risk estimates and Kaplan–Meier survival analyses were performed. Results: A total of 311,380 chemotherapy-treated and 73,814 immunotherapy-treated patients were identified before matching. After propensity score matching, 66,011 patients remained in the chemotherapy cohort and 65,110 in the immunotherapy cohort with well-balanced baseline characteristics. Venous thromboembolism occurred in 2,262 chemotherapy patients (3.4%) and 2,524 immunotherapy patients (3.9%). Immunotherapy was associated with a modestly increased risk of VTE (risk ratio 1.06; odds ratio 1.07; p < 0.01). Kaplan–Meier analysis demonstrated lower VTE-free survival in the immunotherapy group (log-rank p < 0.0001), although proportional hazards assumptions were not met. Conclusions: In this large real-world analysis, immunotherapy was associated with a slightly increased risk of venous thromboembolism compared with chemotherapy in lung cancer patients. These findings highlight the importance of vigilant thrombotic risk assessment in patients receiving immune checkpoint inhibitors. Venous thromboembolism after matching. Treatment Events Total Patients Risk (%) Chemotherapy 2,262 66,011 3.4 Immunotherapy 2,524 65,110 3.9