Venous Thromboembolism (VTE) in Adults with Non Hodgkin Lymphoma (NHL) a Retrospective Cohort Study

Introduction. One major complication of cancer and cancer treatment is venous thromboembolism (VTE). The incidence of thromboembolic complications in patients with hematological malignancies reaches up to 12.1% in patients with acute myeloid leukemia and ranges from 1.5% to 59.5% in patients with lymphoma and these patients had a 10-fold higher risk for the development of venous thrombosis, than patients with lung and gastrointestinal cancers. Known pro-thrombotic risk factors in patients with cancer include; older age, systemic inflammation, central venous catheters (CVCs), thrombophilia, infections/sepsis, obesity, immobilization and advanced disease, but the risk is further increased by chemotherapy, but the trade-off between safety and efficacy of primary thromboprophylaxis in cancer patients treated with chemotherapy is uncertain.

Aim: Aim of our study was to determine incidence of thromboembolic events in patients with NHL and to establish the risk factors and identify patients with prophylactic therapy for thrombosis.

Patients and Methods. We conducted a retrospective cohort study, including all patients registered in the Hematology Department over the age of 18 years diagnosed with NHL between January 2007 and June 2017 in Mexico city.

Results. Data was retrieved from the medical records of all 262 patients (100%) (female 118 , male 149) in a Mexican Hematology Center. The median follow-up was 5.7 years (range 1-10). Only 6 patients (2.2-%) were treated with thromboprophylaxis. The incidence of symptomatic VTE was 1.5% (1- PE, 3- DVT), in the four patients VTE events occurred in the older age category (50-60 years) and all of them with NHL diffuse large B cell lymphoma (DLBCL) and clinical stage III-IV.

In univariate analysis, DLBCL was associated with increased risk of VTE compared to follicular lymphoma (FL) in the first year after diagnosis; this association was no longer significant in adjusted analysis. Major risk factors for VTE included history of VTE before NHL diagnosis, stage III/IV disease and BMI ≥ 30. The cumulative incidence of VTE was highest in the period following diagnosis and decreased over time for both histologies.

While the VTE did not significantly affect the treatment of NHL it caused increased morbidity.

Conclusions. VTE is a relatively uncommon complication of NHL and its treatment, causing increased acute and long-term morbidity. DLBCL is associated with increased risk of VTE compared to FL. This risk is markedly attenuated when adjusting for additional risk factors.The strongest predictors for development of VTE included: time period during chemotherapy administration, history of VTE, clinical stage III/IV and BMI >30. This knowledge can assist clinicians in identifying NHL patients at high risk for VTE.