Venous thromboembolism (VTE) in patients with ALK-rearranged non-small cell lung cancer (ALK-LC): A population-based cohort.

Abstract

6608 Background: Advanced NSCLC is associated with an increased risk for VTE, with a reported rate of 8-15%. Clinical observations suggest a higher rate of VTE in patients with ALK-rearranged NSCLC. Clalit Health Services (CHS) is both a healthcare payer and provider, covering over 50% of the population in Israel, with individual patient data recorded in a centralized electronic database. We aimed to determine the incidence of VTE in patients with ALK-LC using a population-based cohort. Methods: We identified all patients diagnosed with NSCLC between 01/2012-12/2017 within CHS. Clinical and demographic data (including VTE risk factors, i.e. components of the Khorana score) were extracted from the CHS registry for all patients. Patients with ALK-LC were identified according to crizotinib prescriptions (dispensed after an approved CHS' pre-authorization for an ALK-LC diagnosis). VTE was identified by ICD diagnosis codes 415.xx, 444.xx, 451.xx and 453.xx. VTE risk factors (Khorana score) were also extracted. Association between ALK-LC and VTE were analyzed using logistic regression, estimating univariate and multivariate Odds Ratios (OR). Results: Overall, 4327 patients with a diagnosis of NSCLC were identified. 149 (3%) had at least one prescription for crizotinib for advanced ALK-LC. The rate of VTE in these patients was 25% (38 of 149 patients), while in the non-ALK-LC the rate was 14% (596/4178), OR = 2.05, p = 0.0004. The association was significant also in a multivariate analysis adjusting for, age, smoking status, BMI, platelet count, hemoglobin and Charlson co-morbidity score (OR 1.66, p = 0.018). Conclusions: This pooled analysis of individual patient data confirms prior data from smaller retrospective studies, suggesting ALK-LC is associated with a high risk of VTE. Randomized trials with prophylactic anti-coagulation are unlikely to be performed in this rare subtype, thus increased awareness and consideration of VTE prophylaxis in high risk patients is warranted.