Risk scores for occult cancer in patients with unprovoked venous thromboembolism: results from an individual patient data meta‐analysis

BACKGROUND The RIETE and SOME risk scores aim to identify patients with acute unprovoked venous thromboembolism (VTE) at high risk of occult cancer, but their predictive performance is unclear. METHODS The scores were evaluated in an individual-patient data meta-analysis. Studies were eligible if enrolling consecutive adults with unprovoked VTE who underwent protocol-mandated screening for cancer. The primary outcome was a cancer diagnosis between 30 days and 2 years of follow-up. The discriminatory performance was evaluated by computing the area under the receiver (ROC)-curve in random-effects meta-analyses. RESULTS The RIETE score could be calculated in 1,753 patients, of whom 63 (3.6%) were diagnosed with cancer. The pooled area under the ROC-curve was 0.59 (95% CI, 0.52-0.66, I2 =0%). Of the 427 patients (24%) classified as 'high-risk', 25 (5.9%) were diagnosed with cancer compared to 38 of 1,326 (2.9%) low-risk patients (hazard ratio [HR] 2.0; 95% CI, 1.3-3.4). The SOME score was calculated in 925 patients, of whom 37 (4.0%) were diagnosed with cancer. The pooled area under the ROC-curve was 0.56 (95% CI, 0.46-0.65; I2 =46%). Of the 161 patients (17%) classified as 'high-risk' (≥2 points), eight (5.0%) were diagnosed with cancer compared to 29 of 764 (3.8%) low-risk patients (HR 1.2; 95% CI, 0.55-2.7). CONCLUSIONS The predictive discriminatory performance of both scores is poor. When used dichotomously, the RIETE score is able to discriminate between low- and high-risk patients. Since this is largely driven by advanced age, these results do not support the use of these scores in daily clinical practice.