Prevalence of incidental pulmonary thromboembolism in cancer patients: retrospective analysis at a large center

Background: Increased use of routine imaging exams has led to higher rates of incidental diagnosis of pulmonary thromboembolism (PTE), especially for management of disease in cancer patients, among whom it is an important factor in associated morbidity and mortality. Objective: To identify cases of incidental PTE in cancer patients examined with computed tomography (CT) of the thorax, correlating clinical features and associated risk factors. Methods: This is a retrospective study of all episodes of PTE diagnosed between January 2013 and June 2016, selecting cases involving cancer patients and dividing them into two subsets: those with clinical suspicion and those without clinical suspicion of pulmonary embolism (incidental cases). Results: At total of 468 patients had PTE during the period investigated and 23.1% of them were cancer patients, 44.4% of whom exhibited pulmonary embolism as an incidental finding of a chest CT. There was no statistical difference between the two subsets in terms of sex, age, or smoking. In terms of patients’ admission status, 58.3% of the patients without clinical suspicion were outpatients and 41.7% of those with suspicion of PTE were admitted via the emergency room (p < 0.001). The most common cancer sites were lung (17.6%), intestine (15.7%), and breast (13.0%). Patients whose PTE were diagnosed incidentally exhibited a significantly greater rate of metastases, while there were no differences between the groups in terms of chemotherapy, radiotherapy, or recent surgery. Analysis of symptoms revealed that 41.9% of patients without clinical suspicion had complaints suggestive of PTE when they underwent the CT examination. Conclusions: Incidental PTE is common among cancer patients, especially those in outpatients follow-up and in advanced stages of the disease. Patients without clinical suspicion also had symptoms suggestive of PTE when they presented for chest CT.