In this post hoc analysis of the CAP study of apixaban in cancer-associated VTE, patients with incidental VTE differed from those with symptomatic VTE in characteristics and outcomes: VTE recurrence was similar between groups, but incidental VTE was associated with a higher risk of bleeding.
More than half of patients with cancer-associated VTE in the cohort had incidentally detected VTE.
Patients with incidental VTE had different baseline characteristics from symptomatic patients, including lower BMI and more metastatic disease.
The anatomical distribution of VTE differed between groups, with leg deep vein thrombosis far more frequent in symptomatic patients.
Cancer types differed between incidental and symptomatic VTE groups.
Recurrent VTE rates over 36 months did not differ significantly between incidental and symptomatic VTE patients.
Clinically relevant bleeding was more frequent in patients with incidental VTE than in those with symptomatic VTE.
In multivariable analysis, low hemoglobin and incidental VTE were independently associated with bleeding.
This study looked at 284 people with cancer who developed a blood clot (venous thromboembolism) and were treated with the blood thinner apixaban for up to 3 years. About 57% of them had clots that were found by chance, usually on scans done for cancer care, rather than because of symptoms. The researchers compared these 'incidental' clots with clots that caused symptoms. The two groups looked different. People with incidental clots had more advanced (metastatic) cancer, lower body mass index, and more clots in the lungs or abdomen, while symptomatic clots were more often in the leg. Colorectal cancer was more common in the incidental group, and blood cancers and breast cancer in the symptomatic group. The chance of a clot coming back was similar in the two groups (about 10% vs 7%, a difference that could be due to chance). However, clinically relevant bleeding was more common in the incidental group (about 25% vs 13%), and both incidental clots and low hemoglobin were independently linked to bleeding. This research suggests that incidental clots in people with cancer are not necessarily 'milder' and that bleeding risk may deserve particular attention during treatment. Because this was a post hoc analysis of a smaller study, the findings show associations and would need confirmation in larger studies.
Hussaini P, Larsen T, Ghanima W, Astrup Dahm A. (2026). Clinical significance of symptomatic and incidental venous thromboembolism in patients with cancer treated with apixaban.. Research and practice in thrombosis and haemostasis. https://doi.org/10.1016/j.rpth.2026.106968