PURPOSE: This retrospective analysis was designed to determine the incidence of venous and arterial thromboembolic events (TEEs) in lung cancer patients treated with either conventional chemotherapy (CC) alone, immunotherapy (IT) alone, or a combination of the two (C+I).
BACKGROUND: TEEs are a serious complication in cancer patients. Lung cancer is among the more thrombogenic malignancies and platinum-based chemotherapy used commonly in this setting is among the more thrombogenic CC regimens. IT and C+I have an increasing role among frontline management options for advanced stage lung cancers. However, the incidence of TEEs associated with IT agents has not been well characterized.
METHODS: Veterans with lung cancer were retrospectively identified in a VINCI CDW research database by ICD code. Treatment with CC and/or IT, and incidence of and time to TEEs (defined as deep vein thrombosis, pulmonary embolism, stroke, or myocardial infarction) were retrieved from the database using custom queries. Time to TEE was assessed relative to treatment start date, with censoring at a maximum of 180 days.
DATA ANALYSIS : We performed chi-squared tests and Kaplan-Meier time-to-event analyses among CC, C+I, and IT cohorts, controlling for platinum-containing v. non-platinum regimens. RESULTS: We identified 77,472 Veterans (97.7 % male, average age 66) with lung cancer treated between 1992-2019, 93.6% of whom received CC, while 4.5% and 1.9% received C+I or IT, respectively. We observed the highest rate of TEE in the IT cohort (13% v. 7.3% and 5.4% in the CC and C+I cohorts), and found that platinum-based chemotherapy decreased the likelihood of TEE (r = -3.13 and -4.06 for platinum-only and platinum-based with immunotherapy regimens), whereas IT strongly increased the likelihood of TEE (r = 8.05) (p<0.001). Finally, we confirm a decrease in time to TEE between the IT compared with CC and C+I cohorts (average 41 v. 57 and 65 days, respectively; <0.0001).
IMPLICATIONS: We found increased TEEs among lung cancer patients who received frontline IT compared with CC or C+I. With uncertainty in use of prophylactic anticoagulation for ambulatory cancer patients being treated with systemic therapy, cancer-associated TEE incidence and prevention in the IT setting warrants further evaluation.
