Predictors of Mortality in Cancer-Associated Calf Deep Vein Thrombosis

Background: Venous thromboembolism (VTE) is a leading cause of mortality in cancer patients. The outcomes of patients with cancer-associated calf deep vein thrombosis (CDVT), including mortality data, are less understood compared with proximal thrombosis. Aim: To characterize predictors of mortality among cancer-associated CDVT patients. Methods: Single institution inception cohort of cancer-associated CDVT patients who presented with thrombosis distal to popliteal level confirmed objectively by ultrasound, computed tomography or VQ scan were independently reviewed. Active cancer was defined as metastatic disease or use of chemotherapy at diagnosis. The Khorana risk score (KRS) suggested for DVT and mortality prediction in cancer was abstracted based on laboratory tests and cancer type at diagnosis. Institutional review board approval was obtained prior to the analysis. Categorical variables are expressed as percentages and continuous variables as median (interquartile range). SPSS software version 22 was used and Chi-square, Mann–Whitney U and Cox proportional hazard were applied. Results: One hundred nine patients (Men=44 (40%), Age>65=89 (82%), BMI>30=25 (23%), Smoker=59 (54%)) were included. The majority had a low or intermediate KRS (30%-64% respectively). Forty-seven percent died during a median follow-up time of 2.5 years (0.5-3.1). After multivariate analysis, the predictors of mortality were found to be: smoking (Hazard Ratio 2.3; 95%CI 1.2-4.7), metastasis (HR 5.8; 95%CI 2.9-11.7), gastrointestinal cancer (HR 3.9; 95%CI 1.8-8.5), and lung cancer (HR 4.1 95%CI 1.7-10.3). VTE specific variables not associated with mortality included: bilateral CDVT, concomitant pulmonary embolism, multiple vein involvement, filter placement, or a surgery-associated event. Conclusion: Cancer-specific variables and smoking predicted mortality among CDVT patients in this cohort. Neither the KRS nor VTE specific characteristics were predictive of death. A larger study is necessary to further explore these findings.