The risk of venous thromboembolism in cancer patients receiving chemotherapy: a meta-analysis with systematic review

BACKGROUND: The Khorana score was developed to predict the risk of venous thromboembolism (VTE) in cancer patients receiving chemotherapy. However, the utility of the Khorana score remains controversial since different studies report varying results. This meta-analysis aims to analyze the incidence of VTE with different risk stratifications using the Khorana score for overall follow-up time, incidence of deep-vein thrombosis (DVT), incidence of pulmonary embolism (PE) and bleeding in cancer patients receiving chemotherapy. METHODS: A systemic search was performed using PubMed, Embase, Cochrane Library and Web of Science for studies describing VTE incidence in cancer patients undergoing chemotherapy. The incidence of VTE was calculated using R computing software. RESULTS: We included 13 studies in this meta-analysis, with a total of 5,852 cancer patients and 424 VTE cases. Results revealed that overall incidence of low, intermediate and high-risk groups were 2% (95% CI: 1–6%), 11% (95% CI: 6–18%) and 14% (95% CI: 9–20%), respectively. The overall incidence of DVT and PE were 6% (95% CI: 4–10%) and 4% (95% CI: 2–7%), respectively. Lastly, bleeding rate was 4% (95% CI: 2–8%). CONCLUSIONS: According to this meta-analysis, the Khorana score is suitable for cancer patients receiving chemotherapy in a 3–6-month timeframe rather than “forever”. The incidence of PE in this population was significantly greater than what was observed for non-cancer patients. More than half of VTE events occurred within 6 months of commencing chemotherapy.