Arterial and Venous Thromboembolism in ALK-Rearrangement-Positive Non-small Cell Lung Cancer: A Population-Based Cohort Study

INTRODUCTION: There is scarce data regarding the incidence of venous thromboembolism (VTE) and arterial thromboembolism (ATE) in the molecular subtypes of non-small cell lung cancer (NSCLC). We aimed to investigate the association between Anaplastic Lymphoma Kinase (ALK)-positive NSCLC and thromboembolic events. METHODS: A retrospective population-based cohort study of the Clalit Health Services database, included patients with NSCLC diagnosed between 2012 and 2019. Patients exposed to ALK-tyrosine-kinase inhibitors (TKIs) were defined as ALK-positive. The outcome was VTE (at any site) or ATE (stroke or myocardial infarction) 6 months prior to the diagnosis of cancer, until 5 years post-diagnosis. The cumulative incidence of VTE and ATE and hazard-ratios (HR) with 95% CIs were calculated (at 6- 12- 24 and 60-months), using death as a competing risk. Cox proportional hazards multivariate regression was performed, with the Fine and Gray correction for competing risks. RESULTS: The study included 4762 patients, of which 155 (3.2%) were ALK-positive. The overall 5-year VTE incidence was 15.7% (95% CI, 14.7-16.6%). ALK-positive patients had a higher VTE risk compared to ALK-negative patients (HR 1.87 [95% CI, 1.31-2.68]) and a 12-month VTE incidence of 17.7% (13.9-22.7%) compared to 9.9% (9.1-10.9%) in ALK-negative patients. The overall 5-year ATE incidence was 7.6% [6.8-8.6%]. ALK positivity was not associated with ATE incidence (HR 1.24 [0.62-2.47]). CONCLUSIONS: In this study, we observed a higher VTE risk, but not ATE risk, in patients with ALK-rearranged NSCLC relative to those without ALK rearrangement. Prospective studies are warranted to evaluate thromboprophylaxis in ALK-positive NSCLC.