Association of the Khorana Score with development of venous thromboembolism in ovarian cancer.
Authors: Ellen Marcus, Dennis Yi-Shin Kuo, Nicole Suzanne Nevadunsky, Gregory M. Gressel
Journal: Journal of Clinical Oncology (2021)

5555 Background: The Khorana score is a previously validated method to identify patients at high risk of VTE during chemotherapy who would potentially benefit from thromboprophylaxis. The objectives of our study were to evaluate risk factors and timing associated with VTE in a large cohort of ovarian cancer patients and to assess the predictive ability of the Khorana score in this population. Methods: After IRB approval, a retrospective analysis was performed of all patients with ovarian cancer in the Albert Einstein Tumor Registry who received treatment between 2000 and 2020. Demographic, clinical, surgical and histologic data and information regarding timing of VTE were abstracted from the medical record. Khorana scores were retrospectively calculated for all patients who received chemotherapy based on their pre-chemotherapy laboratory indices. Bivariate analysis and multivariable logistic regression were used to examine the association between Khorana score and VTE. Results: A total of 472 patients were included over a median follow-up time of 33.7 (13.3, 61.1) months of whom 142 (31%) underwent diagnostic imaging to rule out VTE. A total of 62 patients (15%) were diagnosed with VTE with a median time from presentation to VTE of 8.7 (2.7, 30.3) months. Individual covariates which were significantly associated with VTE included stage III-IV disease, epithelial histology, open surgery, radical tumor debulking, and presence of residual disease after surgery. Of the 254 patients who received chemotherapy for their disease, 36 (14%) developed VTE within 3 weeks of receiving chemotherapy. Patients with Khorana scores of 2 (OR 1.73 95% CI 0.88-3.42) or 3 (OR 0.89 95% CI 0.33-2.44) were not significantly more likely to develop VTE during chemotherapy compared to patients with a score of 1. However, patients with a score of 4 were 6.74 times more likely to develop a VTE during chemotherapy (95% CI 1.39 - 32.73). Overall, a Khorana score of 2 or higher conferred no significant increased risk of developing VTE during chemotherapy than a score of 1 (OR 1.61 95% CI 0.85- 3.02). In a multivariable model, the Khorana score was not significantly associated with risk of VTE and a Khorana score of 2 or higher could explain only 0.86% of the variability in predicting VTE. The only variables significantly associated with VTE after adjustment were stage III-IV disease and hyperlipidemia. Conclusions: Patients with ovarian cancer are at high risk of developing VTE many months after diagnosis and initiation of chemotherapy. Current ASCO and SGO guidelines recommend thromboprophylaxis for those initiating chemotherapy with a Khorana score of 2 or higher, however our study found that these patients are not at increased risk compared to those with a score of 1. Future models should be developed and validated in large population-based cohorts to determine if there is a more accurate strategy to identify women with ovarian cancer who are at risk for VTE.