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Coagulation & Its Disorders
The Khorana score for prediction of venous thromboembolism in cancer patients:
a systematic review and meta-analysis
Ferrata Storti Foundation
Haematologica 2019 Volume 104(6):1277-1287
Frits I. Mulder,1,2 Matteo Candeloro,3 Pieter W. Kamphuisen,1 Marcello Di Nisio,3 Patrick M. Bossuyt,2 Noori Guman,2 Kirsten Smit,2 Harry R. Büller,2 and Nick van Es2 on behalf of the CAT-prediction collaborators
1Tergooi Hospitals, Department of Internal Medicine, Hilversum, the Netherlands; 2Amsterdam UMC, University of Amsterdam, Department of Vascular Medicine, Amsterdam Cardiovascular Science, Amsterdam, the Netherlands; 3University G. D’Annunzio, Department of Medicine and Ageing Sciences, Chieti, Italy
ABSTRACT
We aimed to evaluate the performance of the Khorana score in pre- dicting venous thromboembolic events in ambulatory cancer patients. Embase and MEDLINE were searched from January 2008 to June 2018 for studies which evaluated the Khorana score. Two authors independently screened studies for eligibility, extracted data, and assessed risk of bias. Additional data on the 6-month incidence of venous thromboembolism were sought by contacting corresponding authors. The incidence in each Khorana score risk group was estimated with random effects meta-analysis. A total of 45 articles and eight abstracts were includ- ed, comprising 55 cohorts enrolling 34,555 ambulatory cancer patients. For 27,849 patients (81%), 6-month follow-up data were obtained. Overall, 19% of patients had a Khorana score of 0 points, 64% a score of 1 or 2 points, and 17% a score of 3 or more points. The incidence of venous thromboembolism in the first six months was 5.0% (95%CI: 3.9-6.5) in patients with a low-risk Khorana score (0 points), 6.6% (95%CI: 5.6-7.7) in those with an intermediate-risk Khorana score (1 or 2 points), and 11.0% (95%CI: 8.8-13.8) in those with a high-risk Khorana score (3 points or high- er). Of the patients with venous thromboembolism in the first six months, 23.4% (95%CI: 18.4-29.4) had been classified as high risk according to the Khorana score. In conclusion, the Khorana score can be used to select ambulatory cancer patients at high risk of venous thromboembolism for thromboprophylaxis; however, most events occur outside this high-risk group.
Introduction
Venous thromboembolism (VTE) is a burdensome and frequent complication in patients with active cancer. The estimated overall 12-month incidence is approxi- mately 6-8% but varies widely across tumor types.1,2 VTE is associated with sub- stantial morbidity and mortality,3 decreases quality of life,4 and can lead to interrup- tion or discontinuation of cancer treatment. Although thromboprophylaxis effec- tively reduces the risk of VTE,5 current guidelines recommend against its routine use in ambulatory cancer patients, probably due to the high number that require treatment, the fear of bleeding, and the considerable burden associated with daily injections of low-molecular-weight heparins.6
Risk stratification tools may help to reduce the number requiring treatment by guiding selection of cancer patients at high risk of VTE. An ideal risk score would help clinicians identify both patients with a negligible risk as well as those at very high risk needing intervention. The best-known risk stratification tool is the Khorana score, which was introduced in 2008. This score assigns points to five clin- ical and pre-chemotherapy laboratory parameters: primary tumor site (+1 or 2
Correspondence:
FRITS I. MULDER
f.i.mulder@amc.nl
Received: October 12, 2018. Accepted: January 2, 2019. Pre-published: January 3, 2019.
doi:10.3324/haematol.2018.209114
Check the online version for the most updated information on this article, online supplements, and information on authorship & disclosures: www.haematologica.org/content/104/6/1277
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haematologica | 2019; 104(6)
1277
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