Incidence, risk factors and the prognostic role of thromboembolic events (TEEs) amongst patients with metastatic pancreatic adenocarcinoma (PAAD): a retrospective, single-center analysis.

Background: Thromboembolic events (TEEs) are frequent among patients with pancreatic adenocarcinoma (PAAD). We set out to estimate the incidence and establish predictive risk factors for TEE and estimate the impact of TEEs on the overall survival (OS) of patients with metastatic PAAD.

Methods: This is a retrospective, single-center study. We included patients with a pathologically confirmed diagnosis of PAAD with distant metastases treated at AC Camargo Cancer Center from 2016 to 2021. We used the competitive risk survival models to estimate the cumulative incidence of TEE. Risk factors for the development of TEEs were evaluated using the competitive risk and logistic regression models. The impact of TEEs on OS was assessed using both landmark and time-dependent covariate Cox survival analyses.

Results: The study population consists of 199 patients. The cumulative incidence of TEEs in 1, 6 and 24 months were 10.1%, 19.3% and 30.2%, respectively. Log₁₀(CA 19-9) was the only factor independently associated with increased risk of TEEs in the logistic regression (Odds ratio = 1.03; 95% confidence interval (95%CI), 1.00-1.06; p = 0.030) and competitive risk survival (Subdistribution hazard ratio = 1.14; 95%CI, 1.02-1.27; p = 0.019) models. In the landmark analysis, early TEEs (within 1 month of diagnosis) were not associated with inferior OS. In the time-dependent covariate Cox proportional hazard model, TEEs were not found to be statistically associated with inferior OS, although there was a trend towards it (Hazard ratio = 1.59; 95%CI, 0.99-2.54; p = 0.051).

Conclusion: TEEs occur in a large fraction of patients with metastatic PAAD. Statistical models with higher predictive performance are currently needed. For the time being, consideration for prophylactic anticoagulation should be done on an individual basis.