Incidental Pulmonary Embolism in Oncology Patients with Current Macroscopic Malignancy: Incidence in Different Tumour Type and Impact of Delayed Treatment on Survival Outcome

Objectives: To evaluate the incidence and outcome of incidental pulmonary embolism (iPE) in patients with current macroscopic malignancy and delayed anticoagulation due to late reporting of CT scan.

Methods: Reports of CT thorax with i.v. contrast done on oncology patients between 1 January 2015 and 31 December 2015 in two district general hospitals in UK were reviewed. Electronic patient records of iPE patients were reviewed for demographic and treatment information.

Results: 26 iPEs were reported in 1,604 scans (731 patients), incidence 1.6%; female = 15; median age = 66 (range 32-90); main artery = 10; lobar artery = 8; segmental = 7; subsegmental = 1; median time (range) from scan to reporting = 1 day (0-60); scan to anticoagulation = 5 days (0-61) (three had no treatment); scan to death = 7 months (1-22+) with nine still alive and two lost to follow up. All had metastatic disease. There was no sudden death. None of the patients whose anticoagulation started more than 5 days after the iPE CT scan died within 3 months. iPE was absent in all repeat staging CT scans (done average 3.4 months after the anticoagulation) in 16 patients, without any anticoagulation in one patient with segmental iPE.

Conclusion: Incidence of iPE in patients with current macroscopic malignancy is low-1.6%-mostly seen in lung, breast and colorectal cancer probably due to frequency of imaging. A few days' delay in anticoagulation does not appear to have an impact on the risk of sudden cardiac death. Advances in knowledge: This study tells us that iPE is infrequent, that it can be treated appropriately with anticoagulation, but this does not necessarily need to begin on the same day of diagnosis.