Predictive Performance of Validated VTE Risk Scores in Setting of Malignancy

Both the PROTECHT and 5-single nucleotide polymorphism (SNP) scores were not more effective at predicting risk for venous thromboembolism (VTE) among patients with cancer than the Khorana score. These findings were published in the Journal of Thrombosis and Haemostasias.

Data were evaluated from the Center for Personalized Cancer Treatment study, a Dutch prospective multicenter study. Enrolled patients were retrospectively assessed by the risk scores Khorana, PROTECHT, and 5-SNP. The Khorana and PROTECHT scores are calculated risk on the basis of 5 and 7 clinical characteristics, respectively, and the 5-SNP score is calculated by the presence of 5 risk loci. Predicted VTE risk scores were compared with incidence of radiologically confirmed VTE.

Patients (N=2729) were aged median 63 (interquartile range [IQR], 55-70) years, 49.2% were women, and the most common cancer types were breast (17.5%), melanoma (12.3%), colorectal (11.4%), and lung (11.1%).

At 6 months, 5.9% of patients developed VTE for an overall incidence rate of 6.4% (95% CI, 5.5%-7.4%). Among patients who developed VTE, 51.9% had a pulmonary embolism, 25.0% a lower-extremity deep-vein thrombosis, and 23.1% another type of VTE. Events were symptomatic (53%) and 41% were incidentally detected.

The discriminatory performance of Khorana was 0.57 (95% CI, 0.55-0.60), PROTECHT was 0.60 (95% CI, 0.57-0.62), and 5-SNP was 0.54 (95% CI, 0.51-0.57).

The proportion of patients who were categorized as high-risk by Khorana was 9.6% and 90.4% were determined to be at low risk. At 6-months, the cumulative incidence of VTE was 11.8% (95% CI, 7.8%-16.7%) among the high-risk and 6.1% (95% CI, 5.1%-7.2%) among the low-risk cohorts; indicating a sensitivity of 16.6% and specificity of 90.8%.

For PROTECHT, 16.8% were categorized as high risk and 83.2% as low risk. The cumulative VTE incidence rates among the high- and low-risk groups were 11.5% (95% CI, 8.5%-15.0%) and 5.6% (95% CI, 4.6%-6.7%), respectively corresponding with a sensitivity of 49.6% and specificity of 67.0%.

Using the 5-SNP criteria, 9.5% were classified as high risk and 90.5% as low risk. The cumulative VTE incidence rates were 10.3% (95% CI, 6.3%-15.4%) for those at high risk and 6.1% (95% CI, 5.1%-7.4%) for those at low risk. Overall, this risk score method had a sensitivity of 28.2% and specificity of 76.0%.

This study may have been limited by the 5% of patients lost to follow-up during the study.

These data indicated that the 5-SNP score did not perform as well for the prediction of VTE among patients with cancer as the validated Khorana score. In addition, the PROTECHT risk score was not superior to Khorana, performing similarly. Overall, additional study is needed to identify more effective factors for predicting VTE risk.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Guman NAM, van Geffecn RJ, Mulder FI, et al. Evaluation of the Khorana, PROTECHT, and 5-SNP scores for prediction of venous thromboembolism in patients with cancer. J Thromb Haemost. Published online August 19, 2021. doi:10.1111/jth.15503