Risk Factors and Outcomes of Subsegmental versus More Central Pulmonary Embolism in Patients with Lung Cancer.

[BACKGROUND] The clinical significance of lung cancer-associated subsegmental pulmonary embolism (PE) remains unclear.

[METHODS] This study retrospectively included 902 patients with lung cancer-associated PE (160 subsegmental PE, 742 more central PE). Cox proportional hazards regression was used to assess the risk of all-cause death. Fine-Gray tests and competing risk models were applied to evaluate the risks (hazard ratio [HR] [95% confidence interval]) of venous thromboembolism (VTE) recurrence and major bleeding. All-cause death was treated as a competing event for both VTE recurrence and major bleeding.

[RESULTS] Compared with the more central PE group, the subsegmental PE group showed no significant differences in the adjusted risks of VTE recurrence (HR 0.99 [0.62-1.57],  = 0.95) and all-cause death (HR 0.83 [0.52-1.34],  = 0.45), and this finding was consistent across subgroups. Compared with patients with subsegmental PE without anticoagulation, those with anticoagulation had a lower adjusted risk of VTE recurrence (HR 0.16 [0.05-0.53],  = 0.003). The adjusted risks of major bleeding (HR 0.30 [0.05-1.70],  = 0.18) and all-cause death (HR 0.43 [0.13-1.42],  = 0.17) did not reach statistical significance. Independent predictors of VTE recurrence included symptomatic deep vein thrombosis (HR 2.71 [1.63-4.52],  < 0.001), tumor-node-metastasis stage (HR 2.07 [1.19-3.60],  = 0.010), mutations (HR 0.62 [0.39-0.98],  = 0.041), and anticoagulation (HR 0.32 [0.20-0.52],  < 0.001).

[CONCLUSION] The risk of recurrent VTE is not miniscule in patients with lung cancer-associated subsegmental PE.