Cancer is not a single disease: is it safe to extrapolate evidence from trials of direct oral anticoagulants in cancer-associated venous thromboembolism to patients with haematological malignancies?

Direct oral anticoagulants in patients with venous thromboembolism and hematological malignancies

Data are needed on direct oral anticoagulants (DOACs) for the treatment of venous thromboembolism (VTE) in hematological malignancies (HM). Retrospective studies to date lacked a control group and did not focus on patients with VTE. Out aim was to assess the incidence of VTE recurrence and bleeding in HM patients treated with low molecular weight heparin (LMWH) or DOACs for acute VTE. This is a retrospective cohort study including patients with active HM and newly-diagnosed VTE, indexed on the first day of anticoagulation and followed for 12 months. The outcome was a composite of recurrent VTE, major bleeding or clinically relevant non-major bleeding. Cumulative incidence [95% confidence interval (CI)] was calculated for each anticoagulation group (LMWH, DOAC) and hazard ratios (HR) were calculated using cox-proportional hazards model, with death as a competing risk. 143 HM patients treated with LMWH (96) or DOACs (47) for acute VTE were included. The most common HM types were lymphoma in 83 (58%) and plasma cell dyscrasia in 32 (22.3%). The 12-month cumulative incidence of the composite outcome was 24.2% (95% CI 15.9-33.5%; n = 22) in the LMWH group and 18.5% (8.5-31.5%; n = 8) in the DOAC group (HR 1.51 [0.695-3.297]). Two recurrent VTE occurred (both in the DOAC group while off-treatment). Nine (9.4%) LMWH-treated patients had major bleeding compared to 1 (2.1%) DOAC-treated patient (HR 4.85 [0.64-36.56]). This study generates the hypothesis that DOACs may be a safe and effective alternative to LMWH for VTE in patients with HM types represented in the study.

Causal relationship between 14 site-specific cancers and venous thromboembolism

BACKGROUND

It has been observed that cancer and venous thromboembolism (VTE) are associated, but anticancer therapy may violate the causality. Therefore, this study aimed to elucidate the causal relationship of various cancers to VTE using Mendelian randomization (MR).

METHODS

Three MR methods were used to estimate causal effects: Inverse variance weighted (IVW), MR-Egger and weighted median. Sensitivity analyses included Cochran's Q-test, MR-Egger intercept test and MR-PRESSO. Gene ontology enrichment analysis was performed to elucidate the underlying mechanisms of VTE development in cancer patients.

RESULTS

The primary IVW approach showed that non-Hodgkin's lymphoma (NHL) might increase the risk of VTE (odds ratio [OR]: 1.20, 95% confidence interval [95% CI]: 1.00-1.44, p = 0.045), while melanoma possibly reduced the risk of VTE (OR: 0.89, 95% CI: 0.82-0.97, p = 0.006), although there was no significance after adjustment for multiple testing. No association was observed between VTE risk and other site-specific cancers. Gene ontology enrichment analysis revealed that vitamin D played an important role in the development of VTE in cancer patients.

CONCLUSIONS

Our findings suggested that genetically predicted NHL was associated with higher VTE risk, whereas melanoma had lower VTE risk compared with other site-specific cancers. Moreover, this study suggested that anticancer therapy and increased extensive examination might play a more important role in VTE development than the nature of cancer.