Polygenic risk scores for prediction of cancer-associated venous thromboembolism in the UK Biobank cohort study

Background: Guidelines recommend thromboprophylaxis for patients with cancer at high risk of venous thromboembolism (VTE). Polygenic risk scores may improve VTE prediction but have not yet been evaluated in patients with cancer. Objectives: We assessed the performance of the 5-, 37-, 297-, extended 297- (additionally including factor V Leiden and prothrombin G20210A), and 100-single-nucleotide polymorphism (SNP) scores in predicting cancer-associated VTE in the UK Biobank, a population-based, prospective cohort study. Methods: The primary outcome was VTE during 12 months after cancer diagnosis. Cancer and VTE diagnosis were based on ICD-10 codes. Discrimination was evaluated by c-indices and subdistribution hazard ratios in the upper vs 3 lower quartiles of the scores in a competing risk model. As a comparison, the c-index was calculated for the Khorana cancer type risk classification. Results: Of 36 150 patients with cancer (median age, 66 years; 48.7% females), 1018 (2.8%) developed VTE. C-indices at 12 months ranged from 0.56 (95% CI, 0.54-0.58) for the 5-SNP to 0.60 (95% CI, 0.58-0.62) for the extended 297-SNP scores. The subdistribution hazard ratios ranged from 1.36 (95% CI, 1.19-1.56) for the 5-SNP to 1.90 (95% CI, 1.68-2.16) for the extended 297-SNP scores and were consistent after adjusting for cancer type. For the Khorana cancer type classification, the c-index was 0.60 (95% CI, 0.58-0.61), which increased to 0.65 (95% CI, 0.63-0.67, +0.05; 95% CI, 0.04-0.07) when combined with the extended 297-SNP score. Conclusion: These findings demonstrate that polygenic VTE risk scores can identify patients with cancer with a 1.9-fold higher VTE risk independent of cancer type. Combined clinical-genetic scores to improve cancer-associated VTE prediction should be evaluated further.