Frequency and Characteristics of Incidental Pulmonary Embolism in Cancer Patients: A Retrospective Study at a Large Oncology Center in Saudi Arabia.

Introduction: Oncology patients are predisposed to incidental-asymptomatic Pulmonary Embolism (PE) which has a substantial morbidity and mortality in untreated patients. As the cancer patients frequently undergo contrast enhanced Computed Tomography (CT) scanning for staging their primary disease, there is a higher chance of detecting unsuspected PE.

Methodology: Our sample included a retrospective review of one-thousand consecutive oncology patients who had CT scan of the chest for reasons other than PE. We excluded females on oral contraceptives, patients who had a prior history of PE or deep veins thrombosis, and history of intensive care unit admission, surgery, trauma, or lower limb fractures within 6 months prior to the CT study. A positive case of incidental PE is considered if it was confirmed by CT pulmonary angiogram study within 24 hours of the staging CT or if there is an agreement for positive PE by two experienced radiologists. The overall incidence of asymptomatic PE in cancer patients, rate of incidental PE in different types and stages of cancer, and location of the PE within the pulmonary vasculature are described.

Discussion: The true incidence, prevalence, and mortality rates of incidental PEs in oncology patients is underestimated due to its silent nature. Since the mortality and morbidity are exceptionally high in cancer patients with incidental pulmonary embolism, staging CT chest examinations should include a meticulous search for incidental PE.

Conclusion: The rate of pulmonary embolism in oncology patients is higher in female and in the advanced stage of the disease. There are certain tumors associated with a higher rate of incidental PEs, which may be related to tumors characteristics or to its treatment.