Risk Scores for Occult Cancer in Patients with Venous Thromboembolism: A Post Hoc Analysis of the Hokusai-VTE Study

Venous thromboembolism (VTE) may be the first sign of an undiagnosed cancer. In patients with unprovoked VTE, the risk is approximately 5% in the year following VTE diagnosis. Cancer-specific screening is therefore often considered in these patients, but the optimal screening strategy remains controversial. Recently, two risk classification scores have been proposed that may help in identifying patients at high risk of occult cancer in whom extensive screening may be warranted. In the present post hoc analysis of the Hokusai-VTE study, we evaluated the performance of the Registro Informatizado de Pacientes con Enfermedad TromboEmbólica (RIETE) and Screening for Occult Malignancy in Patients with Idiopathic Venous Thromboembolism (SOME) scores for occult cancer in patients with acute VTE. A total of 8,032 patients were included in the analysis of whom 218 (2.7%; 95% confidence interval [CI], 2.4-3.1) developed cancer between 30-day and 12-month follow-up. The c-statistics of the RIETE and SOME scores were 0.62 (95% CI, 0.57-0.66) and 0.59 (95% CI, 0.55-0.62), respectively. In patients classified as 'high risk', the cumulative incidence of cancer diagnosis during follow-up was 2.9% (95% CI, 2.1-3.9) for the RIETE score and 2.7% (95% CI, 1.9-3.7) for the SOME score, corresponding to hazard ratios of 1.8 (95% CI, 1.3-2.5) and 1.5 (95% CI, 1.04-2.2), respectively. In conclusion, the performance of both scores was poor. When used dichotomously, the scores were able to identify a group of patients with a significantly higher risk of occult cancer, although it remains unknown whether this translates into improved clinical important outcomes.