Incidentally Diagnosed With Pulmonary Embolism in Lung Cancer Patients: Comparison of Clinical Characteristics and Mortality With Symptomatic Pulmonary Embolism

The purpose of this work was to compare the clinical characteristics, rate of recurrent venous thromboembolism (VTE), bleeding complications and mortality of incidental and symptomatic pulmonary embolism (PE) detected on computed tomography in patients with lung cancer. Clinical data of lung cancer patients with PE were obtained from the Department of Respiratory and Critical Care Medicine of Ningbo First affiliated hospital of Ningbo University during January 2016 and June 2021 and were reviewed retrospectively. We compared clinical and radiological characteristics in lung cancer patients with incidental PE (IPE) and symptomatic PE (SPE) and identified variables associated with the 1-year survival on multivariate Cox analysis. All patients were followed up for 1 year to compare the risks of recurrent VTE, bleeding complications, and mortality. Survival analysis was performed by use of Kaplan–Meier. A total of 223 lung cancer patients with PE were enrolled over the period. Of these, 117 (52%) patients had symptomatic whereas 106 (48%) patients had incidental PE. Those with IPE were more likely to have adenocarcinoma, VTE history, chronic respiratory disease and chemotherapy within 30 days prior to PE, while SPE was more frequently observed in patients with squamous cancer, concomitant VTE, performance status 0-1, chronic heart disease and major surgery within 30 days prior to PE. During 1 year of follow-up, recurrent VTE was diagnosed in 10 patients (9.3%) in lung cancer patients with IPE and 13 patients (11.2%) with SPE. The 12-month cumulative recurrent VTE incidence was 9.6% for patients with incidental and 11.4% for patients with symptomatic PE ( P = .61). The 12-month cumulative incidences of major bleeding complications were also comparable in the 2 groups (8.1% for incidental patients and 9.8% for symptomatic patients; P = .62). However, the respective 12-month mortality risks were 34.6% and 30.2% in lung cancer patients with IPE and SPE respectively ( P = .03). On multivariate Cox analysis, we found that IPE occurrence was an independent risk factor associated with 1-year mortality in lung cancer patients complicated with PE after adjusting for age and sex (HR 1.517; 95% CI: 1.366-1.684; P = .027). Our findings suggest that lung cancer patients diagnosed with and treated for incidental PE had a similar rate of recurrent VTE, and incidence of hemorrhagic complications, but a significantly higher 1-year cumulative mortality rate after PE compared to those with symptomatic PE. IPE may be a marker of poor prognosis.