Clinical relevance of ovarian vein thrombosis and the risk of secondary venous thromboembolic events in women with gynecologic cancers (473)

Objectives: Ovarian vein thrombosis (OVT) is increasingly being identified in women with gynecologic malignancies who undergo surgery. The diagnosis is usually incidental, and the clinical relevance is unclear. Although there is no consensus on the optimal management for OVT, treatments range from observation to anticoagulation. Furthermore, whether OVT places women at increased risk for secondary venous thromboembolism (VTE) events is unknown. This study aimed to identify the incidence of secondary VTE following the initial diagnosis of OVT and the factors that correlate with subsequent VTE. Methods: After IRB approval, a cross-sectional study was conducted among patients diagnosed with OVT from 2012-2020 in a universitybased hospital system. Cases of women with OVT and a cancer diagnosis were identified. The incidence of a secondary VTE and their clinical management with or without anticoagulation was reviewed. Descriptive statistics were performed among the groups to compare baseline characteristics and identify risk factors for secondary VTE. An analysis of cross-sectional imaging was performed to determine if there was an extension of the OVT into the inferior vena cava (IVC) or either renal vein and the length of the clot extension. Numeric variables were compared using the Mann-Whitney U test, and categorical variables were compared using Chi-square or Fischer's exact test. Results: A total of 116 women with OVT and cancer were included. The incidence of secondary VTE was 19% (22 patients). Women with active smoking status or a history of VTE prior to the OVT diagnosis were more likely to develop a secondary VTE (p=0.035 and p=0.021). Women with a history of hormonal contraception or hormone replacement therapy use were less likely to have secondary VTE (p=1). In patients who underwent salpingo-oophorectomy (SO) on the ipsilateral side in which OVT was subsequently diagnosed, the development of secondary VTE event was significantly lower than those OVT patients without prior ipsilateral SO (9.5% vs 30%, p=0.008). Radiographic measurement of OVT extension into the IVC or renal veins was done as both continuous and nominal variables did not confer an increased risk of secondary VTE. Interestingly, there was no difference in the development of secondary VTE in those who were started on anticoagulation in response to OVT diagnosis versus those who were observed (p=0.672). Conclusions: Guidelines for initiating treatment for OVT remain to be determined. Based on our data, women with gynecologic cancer with OVT who are active smokers or have a history of prior VTE are more likely to develop a secondary VTE event. Anticoagulation should be considered for these women. Based on this data, involvement of the IVC or renal vein did not correlate with secondary VTE events and should not be used as a basis for initiating anticoagulation. Patients with OVT diagnosed on the ipsilateral side of prior SO are less likely to develop a secondary VTE. This probably reflects the sequelae of surgery rather than an underlying propensity for thromboembolism.