To Örebro University

BACKGROUND: Routine VTE prophylaxis within 30 days of radical cystectomy (RC) for urinary bladder cancer (UBC) is used to protect from venous thromboembolism (VTE). However, randomized studies and nationwide population-based studies are lacking.

OBJECTIVE: To study VTE and risk factors for VTE in muscle-invasive UBC in a nationwide population-based series, with a focus on the association with RC with and without chemotherapy.

MATERIALS AND METHODS: We studied all patients with clinical stage T2-T4 UBC diagnosed 1997 to 2014 in the Bladder Cancer Data Base Sweden (BladderBaSe). Previous VTE events and risk factors for VTE were registered from 1987. Cox regression analyses and Kaplan-Meier curves were performed to study risk factors for VTE and cumulative incidence of VTE.

RESULTS: In 9720 patients (71% males) with a median age of 74 years 546 (5.6%) had VTE after diagnosis. In Cox analyses controlling for patient's and tumour characteristics, and risk factors for VTE, VTE after diagnosis and first treatment date were associated with chemotherapy with or without RC. Cumulative incidence of VTE increased during 24 months after diagnosis and first treatment date. VTE were less common in patients with previous cardiovascular disease.

CONCLUSION: VTE was commonly observed after 30 days from diagnosis and from first treatment date in patients with T2-T4 UBC, particularly after chemotherapy. The findings suggest that long-term intervention studies of benefit and possible harms of VTE prophylaxis after UBC should be undertaken.