Outcomes among patients with cancer and incidental or symptomatic venous thromboembolism: A systematic review and meta‐analysis

Abstract

Summary Background Patients with cancer have an increased risk of venous thromboembolism (VTE) and it is commonly detected incidentally. The outcomes and optimal management for patients with cancer and incidental VTE remain debated. Objectives We conducted a systematic review and meta‐analysis to evaluate the outcomes in patients with cancer and incidentally detected VTE compared to those with symptomatic events. Patients/Methods We searched the electronic databases and included randomized controlled trials (RCTs) and observational studies reporting recurrent VTE, major bleeding events, and mortality in patients with cancer and incidental VTE compared to symptomatic VTE. Results We included 23 studies for the systematic review: 3 RCTs and 20 observational studies. The meta‐analysis of the 3 RCTs showed a significantly lower rate of VTE recurrence at 6 months in patients with incidental VTE compared to those with symptomatic VTE (relative risk [RR] 0.62, 95% confidence interval [CI] 0.44–0.87). The risk of major bleeding events at 6 months was numerically higher with incidental VTE compared to symptomatic VTE (RR 1.47, 95% CI 0.99–2.20). There was no difference in overall mortality. Conclusions Among patients with cancer, incidental VTE was associated with a lower rate of VTE recurrence compared to symptomatic VTE, with a trend in increased major bleeding events. The risk‐benefit ratio of anticoagulation may differ between incidental and symptomatic events and should be considered in patient management.

Treatment Algorithm in Cancer-Associated Thrombosis: Updated Canadian Expert Consensus

“…Although patients with incidental VTE (i.e., asymptomatic thrombosis found on screening imaging tests) were not included in the RCTs of LMWH vs. VKA [ 8 , 9 , 24 , 25 , 26 ], between 20% and 53% of patients included in the RCTs of DOACs vs. LMWH had incidental VTE at baseline [ 16 , 17 , 18 ]. Although the rate of recurrent VTE is lower in patients with incidental VTE compared to those with symptomatic events (RR: 0.62; 95% CI 0.44 to 0.87), the rate of recurrent events despite anticoagulation remains high [ 31 ]. For example, the results of a subanalysis of patients with incidental vs. symptomatic VTE in the Hokusai-VTE Cancer trial found recurrent VTE occurred in 7.9% of patients with incidental VTE as compared to 10.9% of those with symptomatic VTE [ 32 ].…”

How to treat incidental pulmonary embolism in cancer patients? Recent advances

“…The proportion of patients with incidental cancer-associated VTE varied from 3.8% to 80.8%. In 16 of the 20 observational studies, the overall mortality was lower in patients with incidental events [4].…”

“…To summarize the currently available literature, our group recently conducted a systematic review and meta-analysis to evaluate outcomes in cancer patients with incidentally detected VTE compared to those with suspected events [4]. Our eligibility criteria included studies that enrolled adult patients with cancer-associated VTE and reported the efficacy and safety of anticoagulation in patients with incidental and symptomatic index events.…”

“…The literature reports that more than 90% of patients with incidental VTE receive therapeutic anticoagulation. Hence, data on outcomes in patients not treated with anticoagulation remained very limited and often biased towards those with poorer prognoses [4]. An individual patient data meta-analysis from 11 registries shed some light on the outcomes of cancer-associated incidental PE when patients were left untreated [18].…”

“…Still, the clinical significance of incidental PE does not seem to differ according to the underlying risk factors [2]. Most recent data suggest approximately 50% of all cancer-related PE are detected on diagnostic imaging obtained for reasons other than suspicion of venous thromboembolism (VTE) [3,4].…”