Prevalence and Clinical Significance of Incidental and Clinically Suspected Venous Thromboembolism in Lung Cancer Patients

BackgroundIt is unclear what proportion of VTE events in lung cancer patients are incidentally discovered and whether incidental events affect mortality.Patients and MethodsWe conducted a retrospective cohort study of lung cancer patients seen at the University of Rochester between January 1, 2006 and December 31, 2008 with the goal of quantifying and characterizing VTE events. Multiple clinical variables and mortality outcomes were compared using Kaplan-Meier survival analysis and multivariate Cox proportional hazards.ResultsThe study population consisted of 207 subjects with lung cancer. The median age was 66 years and 55% were female (n = 115). Thirty-one patients (14.9%) experienced at least 1 VTE event with 32.2% (10/31) of these incidentally discovered. Incidental events comprised 29.4% (n = 5) of pulmonary embolisms, 11.1% (n = 2) of deep vein thrombosis, and 100% (n = 3) of visceral events. The median survival for patients with incidental VTE was 23.4 months (95% confidence interval [CI], 4.8-32.1) compared with 45.8 months (95% CI, 34.1-56.8) in patients without VTE (HR 2.4; 95% CI, 1.2-4.9; P = .01), but in a subgroup analysis of stage IV patients overall survival was not significantly different (HR, 0.94; P = .33). Patients with clinically suspected VTE had the lowest median survival at 13.1 months (95% CI, 6.4-18.9) which was significantly lower than patients without VTE (HR, 2.7; 95% CI, 1.6-4.5; P = .002), but not significantly different from patients with incidental VTE (HR, 1.2; 95% CI, 0.4-2.0; P = .7). In multivariate analysis, occurrence of VTE (HR, 2.3; 95% CI, 1.3-3.8; P = .002) was significantly associated with mortality when adjusting for age, stage, and histology.ConclusionsOne-third of VTE events in lung cancer patients are incidentally discovered and VTE has negative clinical effect in lung cancer patients.