The ALK Rearrangement is a Major Risk Factor for Venous and Arterial Thrombosis in Non-Small Cell Lung Cancer

Venous thromboembolism (VTE) is a common cause of morbidity and mortality in cancer patients and leads to a significant increase in health care costs. Several risk prediction scores to identify cancer patients at high risk of VTE have been proposed, but their clinical usefulness remains a matter of debate, especially as it relates to non-small cell lung cancer (NSCLC). Hanny Al-Samkari, M.D., of Massachusetts General Hospital in Boston, MA, suggested on Monday during the Virtual Venous Thromboembolism and Cardioembolism session that this could possibly be due to the tumor molecular subtype being omitted. Previous research suggested a possible increased VTE risk in ALK-rearranged NSCLC, but data are conflicting. As such, evaluating the thrombotic risk conferred by the ALK rearrangement was the aim of Al-Samkari and team.

Their retrospective cohort study of 807 advanced-stage NSCLC patients diagnosed between 2009 and 2019 reported on both ALK-rearranged (N = 422) and non–ALK-­rearranged (N = 385) NSCLC patients. As compared to the non-ALK NSCLC patients, ALK patients were younger, had better performance status, and had significantly lower rates of most VTE risk factors but also had a significantly high rate of VTE. Al-Samkari remarked that in time-to-event analyses controlling for thrombosis risk factors, the ALK rearrangement conferred a 4-fold increase in VTE risk and a 3-fold increase in arterial thrombosis risk in NSCLC. This suggests that these patients may be considerably more likely to benefit from pharmacologic thromboprophylaxis.