Some patients with cancer with a non-O blood type may be at an increased risk of venous thromboembolism (VTE), according to research published in Blood Advances.

Some evidence suggests that patients with cancer are as much as 15 times more likely to develop VTE than are members of the general population.

Given, however, that patients with cancer may also have an increased risk of bleeding, prophylaxis is not generally recommended. Targeting prophylaxis to only those patients most likely to benefit is therefore an area of active inquiry.

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Previous research has suggested that ABO blood type is predictive of VTE risk, and that blood type is linked with nearly one-third of VTE events in the general population, although the causal mechanisms are not fully understood. For this study, researchers investigated whether ABO blood type is linked with VTE risk among patients with cancer.

Overall, data from 1708 patients with cancer were included in the present analysis. The median patient age was 61 years, 46% of patients were female sex, and the most common tumor type was lung (19%). The majority (58%) of patients had intermediate-risk disease. ABO blood types included O-type (38%), A (40%), B (15%), and AB (7%).

The median follow-up was 24 months; by this point, 8.8% of patients had developed a VTE. Analysis showed that during the initial 3 months of follow-up, the time-restricted subdistribution hazard ratio (SHR) for VTE risk for non-O blood type was 1 (95% CI, 0.6-1.67), suggesting there was no association. After 3 months, however, among patients with intermediate- or low-risk thrombotic tumors, there appeared to be such an association (SHR, 1.79; 95% CI, 1.12-2.85).

This link was not present among high-risk tumor types (SHR, 0.94; 95% CI, 0.55-1.61) and was weaker after adjusting for factor VIII status.

“ABO blood type group is an easily accessible VTE predictor that can help in the clinical practice during risk assessment in patients with cancer,” the authors wrote in their report.


Englisch C, Moik F, Nopp S, Raderer M, Pabinger I, Ay C. ABO blood group type and risk of venous thromboembolism in patients with cancer. Blood Adv. 2022;6(24):6274-6281. doi:10.1182/bloodadvances.2021006283

This article originally appeared on Hematology Advisor