Evaluation of Risk Assessment Models for Predicting Venous Thromboembolic Events in Cancer Patients Using Implanted Central Venous Access Devices

Introduction

Cancer patients are at an increased risk of venous thromboembolic events (VTEs). Implanted central venous access devices (ICVADs) are commonly used for administering chemotherapy and may further increase the risk of VTEs. Our study aims to evaluate the incidence and predictors of VTEs, utilizing the commonly used VTE risk assessment models (RAMs), in cancer patients receiving chemotherapy through ICVADs.

Methods

Medical records data of adults (≥18 years) who received chemotherapy through ICVADs from January 2022 until December 2023 were retrospectively reviewed. Patients on therapeutic anticoagulation at the time of ICVAD insertion were excluded.

Khorana, COMPASS and ONCOTEV RAMs were calculated as previously described. No routine imaging studies were performed to detect asymptomatic VTEs.

VTEs were defined as venous thrombotic events reported after insertion of ICVAD until six months post-removal. Patient characteristics and VTE frequency were compared using Fisher’s exact and Mann Whitney U tests. Overall survival (OS) was calculated using the Kaplan Meier method and compared using log-rank test.

Results

A total of 264 patients with a median age of 56 (range: 22-81) years were included in the analysis. The most common cancer types were gastric (n=78, 29.5%), colorectal (n=61, 23.1%), pancreatic (n=51, 19.3%), and breast (n=45, 17%). 148 (56.1%) had metastatic disease.

According to RAMs, 72 (27.3%) had Khorana score >2, 131 (49.6%) had COMPASS score >6, and 42 (15.9%) had ONCOTEV score >1.

During a median follow-up of 11.8 (range: 0.2-29.6) months, VTEs were reported in 51 (19%) of patients, occurring at a median of 3.6 (range: 0.1-20.3) months after ICVAD insertion. 27 (53%) were line related. VTEs were more frequent in patients with history of diabetes (p=0.02), a white blood cell count > 11 X 103/μL at the time of line insertion (p=0.037), and when the time from diagnosis to line insertion was >6 months (p=0.038).

When evaluating the three RAMs for correlation with VTE, there was no significant correlation between VTEs and Khorana (VTE rates: 16% in the low-risk group and 22% in the high-risk group, p=0.075) or COMPASS (VTE rates: 17% in the low-risk group and 21% in the high-risk group, p=0.4) risk groups. However, VTEs were significantly correlated with the ONCOTEV risk (VTE rates: 17% in the low-risk group vs 31% in the high-risk group, p=0.037). The occurrence of VTEs was associated with inferior OS, with 1-year OS rates of 63% vs 75%, (p=0.028).

Conclusion

Cancer patients receiving chemotherapy through ICVAD are at high risk for VTEs. Among the assessed models, ONCOTEV RAM was the most effective to predict VTEs in this group of patients. Further studies are needed to explore the potential role of prophylactic anticoagulation in this context.