Incidence, risk factors, and evolution of venous thromboembolic events in patients diagnosed with pancreatic carcinoma and treated with chemotherapy on an outpatient basis

Background: Pancreatic carcinoma is one of the tumors associated with a higher risk for thromboembolic events, with incidence rates ranging from 5% to 41% in previous retrospective series. Patients and methods: We conducted a retrospective study in eleven Spanish hospitals that included 666 patients diagnosed with pancreatic carcinoma (any stage) between 2008 and 2011 and treated with chemotherapy. The main objective was to evaluate the incidence of venous thromboembolic events (VTE) in this population, as well as potential risk factors for thrombosis. The impact of VTE on mortality was also assessed. Results: With a median follow-up of 9.3 months, the incidence of VTE was 22.1%; 52% were diagnosed incidentally. Our study was unable to confirm the ability of the Khorana score to discriminate between patients in the intermediate or high risk category for thrombosis. The presence of VTE proved to be an independent prognostic factor associated with increased risk of death (HR 2.39, 95% CI 1.96-2.92). Symptomatic events correlated with higher mortality than asymptomatic events (HR 1.72; 95% CI, 1.21-2.45; p = 0.002), but incidental VTE, including visceral vein thrombosis (VVT), negatively affected survival compared to patients without VTE. Subjects who developed VTE within the first 3 months of diagnosis of pancreatic carcinoma had lower survival rates than those with VTE after 3 months (HR 1.92, 95% CI 1.30-2.84; p<0.001). Conclusions: Pancreatic carcinoma is associated with a high incidence of VTE, which, when present, correlates with worse survival, even when thrombosis is incidental. Early onset VTE has a particularly negative impact.