The clinical utility of the Khorana score in determining risk for venous thromboembolism in patients with gynecologic cancer

Abstract

Objectives: Venous thromboembolism (VTE) is a significant cause of morbidity and mortality in patients with gynecologic cancer. The Khorana Score (KS) is a risk stratification tool for VTE that has been validated across multiple cancer types and ASCO recommends consideration of VTE chemoprophylaxis among cancer patients with KS of 2 or above. The best KS for initiating VTE chemoprophylaxis among gynecologic oncology patients has not previously been evaluated. The purpose of this study was to evaluate the clinical utility of the KS among patients with gynecologic cancer. Methods: A retrospective review was completed of all chemotherapy-naive patients who initiated treatment for gynecologic cancer at our institution between December 2019 and December 2020. Demographic, oncologic, clinical and laboratory data was collected. KS was calculated for all patients using previously specified parameters of cancer type, pre-chemotherapy leukocyte count >11, pre-chemotherapy hemoglobin 300 and BMI >35. Patients were also assessed for history of VTE during treatment and history of inpatient admission for therapeutic anticoagulation. Multivariate logistic regression analyses were completed to assess risk factors for VTE. Results: A total of 62 patients met inclusion criteria. Median age was 64 years. The majority of patients reported White race (82%), had ovarian cancer (39%), and advanced stage disease (57%). The majority of patients had a KS of 2 or above (52%). Median KS was 2 (Range= 1-4). During treatment, 7 (11.3%) of patients were diagnosed with VTE. The majority of VTE occurred in patients with KS of 3 or above (n=4, 57%). A logistic regression was performed to evaluate associations between age, stage, race, and KS on VTE diagnosis. Increasing KS was noted to be associated with increased risk of VTE (OR 4.9, p=0.01). When using a cut-off KS of 2 or greater, no significant increase in VTE was noted. However, when using a cut-off KS of 3 or greater, patients were 15 times more likely to have VTE (OR 15.2, p=0.04). Conclusions: Previous studies have reported that cancer patients with KS of ≥ 2 are at high risk for VTE with incidence as high as 10.2% within 6 months of starting chemotherapy. Clinical practice guidelines recommend consideration of VTE chemoprophylaxis for patients with KS ≥2 who are starting chemotherapy in the outpatient setting. In our gynecologic oncology population, KS ≥2 was not associated with increased VTE risk. The most notable increase was found in those with KS ≥3. These results suggest that KS of 3 may be a more appropriate cutoff to determine risk for VTE and guide clinical management regarding VTE prophylaxis in patients with gynecologic cancer.