PO55 | HISTORY OF CANCER IN PATIENTS WITH SEVERE HEREDITARY THROMBOPHILIA VERSUS NO THROMBOPHILIA: A SINGLE-CENTER COHORT OF PATIENTS WITH VENOUS THROMBOSIS

Introduction. Hypercoagulability is a hallmark of cancer and may contribute to tumor progression. Severe hereditary thrombophilia represents a lifelong prothrombotic condition, but its association with cancer remains unclear. Aim. To compare the prevalence of cancer in patients with severe hereditary thrombophilia versus patients without thrombophilia. Methods. We conducted a single-center observational study including consecutive patients with venous thrombosis. Patients were classified as having severe hereditary thrombophilia or no thrombophilia based on standardized testing. The primary outcome was history of cancer (ever cancer), defined as any solid or hematological malignancy diagnosed at any time. Age at thrombosis was used as age at study inclusion. Cancer prevalence was compared using Poisson regression models with log link and robust standard errors to estimate prevalence ratios (PR), adjusted for age and sex. Results. A total of 400 patients were included (200 with severe hereditary thrombophilia and 200 without) (Tab 1). Cancer prevalence was similar between groups (11.0% vs 12.5%). In multivariable regression adjusted for age and sex, severe hereditary thrombophilia was not associated with a higher prevalence of cancer (PR 1.33, 95%CI 0.67–2.58, p=0.403). Increasing age was independently associated with cancer prevalence (PR per year 1.05, 95%CI 1.03–1.07, p