Abstract: Objective To investigate the risk factors, clinic charactertics and survival prognosis of pulmonary embolism (PE) in patients with lung cancer. Methods The clinic data of 28 lung cancer patients with PE, hospitalized in department of respiratory and critical care medicine of Tianjin Chest Hospital between June 2012 to June 2015, were retrospectively reviewed. Eleven of them were diagnosed with primary lung cancer and PE (symptomatic group), and 17 lung cancer patients were found PE accidentally (asymptomatic group). A total of 56 lung cancer patients without PE were used as control subjects (no PE group). Data of pathological types, clinical staging of lung cancer, systemic chemotherapy, white blood cell (WBC), hemoglobin (Hb), platelet (PLT), D- dimer (DD), albumin (ALB) and C- reactive protein (CRP) were analyzed by univariate analysis in the symptomatic group and asymptomatic group. Logistic regression analysis was carried out on the statistically significant indexes to observe the influencing factors. The morphology and location of the remobilization images were analyzed in lung cancer patients with PE. The median time to embolism and survival of PE patients were compared between symptomatic group and asymptomatic group. Results The proportion of adenocarcinoma,systemic chemotherapy and stage Ⅲ + Ⅳ were significantly higher in PE group than those in no PE group (P < 0.01). The ratio of white blood cells (WBC)> 11×109/L (hyperleukocytosis) and albumin (ALB) <30 g/L and D-dimer (DD)> 0.5 mg/L were significantly higher in PE group than those of no PE group (P < 0.05). There were no statistical differences in other indicators including clinical symptoms between the two groups (P > 0.05). The logistic regression analysis showed that adenocarcinoma, chemotherapy, WBC>11×109/L and DD>0.5 mg/L were the risk factors of lung cancer with PE (P < 0.05).There was higher ratio of asymptomatic PE in lung cancer patients with PE. There were no significant differences in morphology and location of the remobilization images in symptomatic group. The median time of embolization was 3.6 months(95% CI: 3.2- 4.0) in the asymptomatic group, which was significantly earlier than that in the symptomatic group (10.5months, 95% CI: 8.88-12.12, P < 0.01). The median survival time was 7.2 months (95% CI: 5.86-8.56) in the asymptomatic group, which was significantly longer than that of symptomatic group (2.8 months, 95% CI: 2.48- 3.12, P < 0.05).Conclusion Lung adenocarcinom, systemic chemotherapy, hypoproteinemia and increased D-dimer are the independent risk factors in lung cancer patients with PE. PE in lung cancer is frequently asymptomatic in the early stage. Compared to symptomatic patients, asymptomatic cases have better prognosis.

Key words: lung neoplasms, pulmonary thromboembolism, risk factors, survival time