Incidental Pulmonary Embolism in Cancer Patients: Clinical Features and Outcome.
Authors: Piacentini Giulia , Fregoni Vittorio , Rizzo Gianpiero , Prada Gian Antonio Da , Lorenzetti Isabella Thea , Gallizzi Giulia , Pavesi Lorenzo , Riccardi Alberto 
Published: October 2019

Abstract
Abstract 2243

Background:
Incidentally diagnosed pulmonary embolism (IPE) in patients with malignancy is a grooving problem. With improvements in the quality of computed tomography (CT) examinations, pulmonary embolism is increasingly being detected incidentally in patients undergoing routine cancer staging CT scans.
Determining the clinical significance of these incidental findings on the prognosis of cancer patients could be of relevance.

Methods:
We conducted a retrospective cohort study of cancer patients at Oncology Unit of IRCCS Fondazione Maugeri Pavia (Italy) from 2008 to 2011. A total of 2500 oncology patients were valuated. Adult patients (age >18 Years) with objectively proven pulmonary embolism (PE) were eligible. Multiple clinical variables and mortality outcomes were collected. Incidence and standard deviation were calculated for quantitative variables, while frequency and percentage for qualitative ones. Finally, the comparison between clinical variables and outcomes of patients with symptomatic pulmonary embolism than those with IPE, was performed using the Chi-squared test.

Results:
Between January 2008 and January 2011, fifty patients (2%) with established PE and malignancy were identified. The mean age (±SD) of patients was 70,0 (±8,3). The 42,3% of patients were females and 57,7% were males. None had a history of hereditary thrombophilia.
In 24 of patients the diagnosis of pulmonary embolism (PE) was driven by the clinical presentation while in the 26 remaining cases the detection was clinically unsuspected. These last the IPE was found or during the baseline staging (23%) or during the restaging after therapy (77%).
The cumulative incidence was found to be 0,95% in the IPE group and equal to 0,87% in the other one. Sex was not statistically significantly associated with symptomatic or asymptomatic presentation.
Most patients with IPE had advanced-stage disease at the time of PE diagnosis: 20 (76,9%) patients had stage IV, whereas only 6 (23.1%) patients had stages I, II or III disease. The staging was significantly associated with incidental events respect to symptomatic ones (76,9% for patients with stage IV disease vs 50% for patients with stage I to III disease, p < 0,05).
An active (within 30 days) treatment with chemotherapy or hormone therapy was related to incidental finding (65,4% of IPE vs 37,5% in symptomatic group), with significant statistical value. (p<0,05)
There was no difference between the groups based on the tumor type or the location of the embolus in pulmonary vasculature. Mortality at one year was 33,2% in the symptomatic group and 30,7% in the IPE group (p > 0,05).

Conclusion:
IPE occurs in 52% of pulmonary embolism in cancer patients. The cumulative incidence and mortality per year compared to symptomatic thrombotic events are similar. Recent chemotherapy treatment (< 3 months) and advanced stage are risk factor for IPE. In our series there is no relationship to the tumor site. Current guidelines recommend antithrombotic prophylaxis for patients with cancer who are admitted to the hospital for medical illness (administered for the duration of the hospital stay) and for patients who have undergone surgery for cancer (extended for up to 5 weeks) but not for routine use in ambulatory patients receiving chemotherapy. Our findings required reconsideration of prognosis and anticoagulation options in cancer patients with advanced disease and chemotherapy treatment recently.

Disclosures:
No relevant conflicts of interest to declare.