Clinical history of cancer-associated splanchnic vein thrombosis.

Background: Cancer represents a risk factor for splanchnic vein thrombosis (SVT) and usual site venous thromboembolism (VTE).

Objectives: To compare characteristics and outcomes of patients with cancer-associated SVT and usual site VTE.

Patients/methods: Patients with solid cancer and SVT were enrolled in an international, prospective registry between May 2008 and January 2012. The comparison cohort included (1:1 ratio) patients with solid cancer and usual site VTE treated at two thrombosis centers who had a minimum of 12 months follow-up at December 2019 or experienced one of the outcomes within 12 months follow-up. Recurrent VTE, major bleeding, and all-cause mortality were evaluated at 12-month follow-up.

Results: A total of 264 patients (132 in each cohort) were enrolled. Patients with SVT were less likely to have metastatic disease (36.1% vs 72.5%) or receive cancer therapy at thrombosis diagnosis (29.6% vs 64.9%). The most frequent cancer types were hepatobiliary and pancreatic in the SVT cohort and gastrointestinal in the usual site VTE cohort. Fewer patients with SVT received anticoagulation (68.9% vs 99.2%), and treatment duration was shorter (6.0 vs 11.0 months). The cumulative incidence of major bleeding (2.3% vs 4.7%) was nonsignificantly lower in the SVT cohort, whereas recurrent thrombosis (4.7% vs 5.5%) and all-cause mortality (41.7% vs 39.4%) were comparable between the two cohorts.

Conclusions: The risk of recurrent thrombosis and bleeding appears to be similar in cancer patients with SVT and cancer patients with usual site VTE, despite some differences in baseline characteristics and anticoagulant treatment. Further prospective studies are warranted to confirm these findings.