Incidence, determinants and the transient impact of cancer treatments on venous thromboembolism risk among lymphoma patients in Denmark

Thrombosis risk prediction in lymphoma patients: A multi-institutional, retrospective model development and validation study

Venous thromboembolism (VTE) poses a significant risk to cancer patients receiving systemic therapy. The generalizability of pan-cancer models to lymphomas is limited. Currently, there are no reliable risk prediction models for thrombosis in patients with lymphoma. Our objective was to create a risk assessment model (RAM) specifically for lymphomas. We performed a retrospective cohort study to develop Fine and Gray sub-distribution hazard model for VTE and pulmonary embolism (PE)/ lower extremity deep vein thrombosis (LE-DVT) respectively in adult lymphoma patients from the Veterans Affairs national healthcare system (VA). External validations were performed at the Harris Health System (HHS) and the MD Anderson Cancer Center (MDACC). Time-dependent c-statistic and calibration curves were used to assess discrimination and fit. There were 10,313 (VA), 854 (HHS), and 1858 (MDACC) patients in the derivation and validation cohorts with diverse baseline. At 6 months, the VTE incidence was 5.8% (VA), 8.2% (HHS), and 8.8% (MDACC), respectively. The corresponding estimates for PE/LE-DVT were 3.9% (VA), 4.5% (HHS), and 3.7% (MDACC), respectively. The variables in the final RAM included lymphoma histology, body mass index, therapy type, recent hospitalization, history of VTE, history of paralysis/immobilization, and time to treatment initiation. The RAM had c-statistics of 0.68 in the derivation and 0.69 and 0.72 in the two external validation cohorts. The two models achieved a clear differentiation in risk stratification in each cohort. Our findings suggest that easy-to-implement, clinical-based model could be used to predict personalized VTE risk for lymphoma patients.

Cancer-associated thrombosis in hematologic malignancies

Patients with hematologic malignancies are often complicated not only by severe bleeding due to thrombocytopenia and disseminated intravascular coagulation but also by thromboembolic events, just like in patients with solid cancers, and these events can negatively impact patient outcomes. Nevertheless, the prevention and treatment of cancer-associated thrombosis (CAT) in hematologic malignancies has not been adequately investigated due to the limited size, heterogeneity, and unique pathophysiology of the patient population. This article summarizes the current understanding, risk factors, prediction models, and optimal prevention and treatment strategies of CAT in hematologic malignancies on a disease-by-disease basis, including acute leukemia, lymphoma, myeloma, and myeloproliferative neoplasms. Specific considerations of novel molecular targeted therapeutics introduced in recent years, such as immunomodulatory drugs and tyrosine kinase inhibitors, are also discussed based on the latest clinical trials.

Venous-thromboembolism and associated health care utilization in elderly patients with diffuse large B cell lymphoma

BACKGROUND

Patients with lymphoma have an increased risk of venous thromboembolism (VTE). The authors examined the risk of VTE and subsequent health care utilization in elderly patients with diffuse large B cell lymphoma (DLBCL).

METHODS

A total of 5537 DLBCL patients ≥66 years old enrolled in Medicare from the Surveillance, Epidemiology, and End Results registry and a noncancer control group of Medicare beneficiaries (n = 5537) were identified. Cumulative incidence function to examine the risk of VTE 12 months after DLBCL diagnosis was used. Fine and Gray method was used to examine the risk factors associated with VTE risk in multivariable models. Total number of hospitalizations, outpatient visits, and Medicare spending were compared in DLBCL patients with and without VTE.

RESULTS

VTE was diagnosed in 8.3% DLBCL patients and 1.5% controls, yielding an 8.6-fold higher risk of VTE in DLBCL in adjusted analysis (95% confidence interval [CI], 6.62-11.20; P < .001). Multivariable regression analysis showed that precancer VTE history was associated with an increased risk of developing VTE after a DLBCL diagnosis (hazard ratio [HR], 5.39; 95% CI, 4.39-6.63), and Asian individuals were associated with a lower risk (HR, 0.54; 95% CI, 0.29-1.00). Patients newly diagnosed with VTE after lymphoma had a 1.7-fold higher rate of hospitalization and a 1.2-fold higher rate of outpatient visits compared to those without, resulting in excess Medicare spending of $22,208 in the first year after DLBCL diagnosis.

CONCLUSIONS

Elderly patients with DLBCL have an elevated risk of VTE resulting in excess health care utilization. VTE history before DLBCL was associated with increased risk of post-DLBCL VTE, and Asian individuals were associated with a lower risk of VTE.

How I treat and prevent venous thrombotic complications in patients with lymphoma

Venous thromboembolism (VTE) is a common complication occurring in 5-10% of patients with lymphoma. As the complexity of lymphoma management has increased with novel therapies, so too has the treatment of VTE. Therapeutic options for the treatment of cancer-associated VTE have expanded from only warfarin and low-molecular-weight heparins (LMWHs) to include the direct oral anticoagulants (DOACs) apixaban, edoxaban and rivaroxaban. There have been no head-to-head trials comparing different DOACs in this setting and randomized trials comparing a DOAC with LMWH dalteparin differ in trial design and results. Drug-drug interactions, drug-specific side effects and patient selection are important considerations when prescribing anticoagulant therapy. In all patients, the relative risks of thrombosis and bleeding, the availability of the anticoagulant, and the life expectancy of the patient are vital elements in selecting the most appropriate anticoagulant (which can vary over time) for the individual patient. We describe the intricacies and challenges of treating thrombotic complications in patients with lymphoma with an emphasis on evidence and guideline-based care.

A novel nomogram based on prognostic factors for predicting venous thrombosis risk in lymphoma patients

Lymphoma-associated venous thromboembolism (VTE) can be a serious complication in lymphoma patients. We designed a nomogram as a guide to estimate the VTE risk in lymphoma patients. We retrospectively analyzed 555 Chinese lymphoma patients who were newly diagnosed at West China Hospital. The nomogram was generated based on multivariate regression coefficients. The multivariate analysis indicated that advanced clinical stage (p < .001*), Hodgkin lymphoma (p = .045*), and prechemotherapy Hb level <115 g/L (p = .01*) were independent risk factors for VTE in lymphoma patients. A calibration plot and the area under the receiver operating characteristic curve were used to validate the novel nomogram. The nomogram displayed a good C-index (0.73), and the calibration plot showed excellent agreement between the predicted and actual probabilities. The AUROC of the nomogram was 0.731, demonstrating a strong discriminatory ability. Notably, the predictive value of the nomogram was better than the Khorana risk score.

Aggressive lymphoma subtype is a risk factor for venous thrombosis. Development of lymphoma - specific venous thrombosis prediction models

Venous thromboembolic events (VTE) are a frequent complication of lymphoma. We conducted a retrospective analysis to compare VTE risk in diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL). Subjects were randomly assigned to training and validation sets to identify risk factors of VTE and evaluate risk model performance, including the Khorana score. A group of 790 patients were diagnosed from 2002 to 2014 (DLBCL = 542, FL = 248). Median follow- up was 49 months. We observed 106 VTE, with higher incidence in DLBCL (5-year cumulative incidence = 16.3% vs 3.8% in FL patients). Five-year OS for patients with VTE was 51.4% vs 73.1% in patients without VTE (P < .001). Baseline VTE risk factors identified in the training cohort included lymphoma subtype, previous VTE, ECOG performance status ≥2, decreased albumin, increased calcium, elevated WBC, absolute lymphocyte count or monocyte count, and presence of bulky disease. Addition of new variables to the Khorana score improved its performance measured by Akaike information criterion and Concordance index. A new risk model including lymphoma subtype, albumin, WBC count, and bulky disease was validated in time-based ROC analyses. These findings were confirmed in the validation cohort. Lymphoma subtypes have different VTE risk. The effect of lymphoma subtype was independent from disease burden and the use of systemic therapy. The Khorana risk-score was validated in time to event analyses, and a more robust lymphoma-specific VTE risk score is proposed. These findings suggest lymphoma patients with highest VTE risk can be identified with baseline parameters.

Venous Thromboembolism in Lymphoma: Risk Stratification and Antithrombotic Prophylaxis

Lymphoma is listed among the neoplasias with a high risk of venous thromboembolism (VTE). Risk factors for VTE appear to differ from risk factors in solid tumors. We review the literature of the last 20 years for reports identifying these risk factors in cohorts consisting exclusively of lymphoma patients. We selected 25 publications. The most frequent studies were analyses of retrospective single-center cohorts. We also included two reports of pooled analyses of clinical trials, two meta-analyses, two analyses of patient registries, and three analyses of population-based databases. The VTE risk is the highest upfront during the first two months after lymphoma diagnosis and decreases over time. This upfront risk may be related to tumor burden and the start of chemotherapy as contributing factors. Factors consistently reported as VTE risk factors are aggressive histology, a performance status ECOG ≥ 2 leading to increased immobility, more extensive disease, and localization to particular sites, such as central nervous system (CNS) and mediastinal mass. Association between laboratory values that are part of risk assessment models in solid tumors and VTE risk in lymphomas are very inconsistent. Recently, VTE risk scores for lymphoma were developed that need further validation, before they can be used for risk stratification and primary prophylaxis. Knowledge of VTE risk factors in lymphomas may help in the evaluation of the individual risk-benefit ratio of prophylaxis and help to design prospective studies on primary prophylaxis in lymphoma.

Long-Term Risk of Venous Thromboembolism in Survivors of Childhood Cancer: A Report From the Childhood Cancer Survivor Study

Purpose To estimate the incidence of late-occurring venous thromboembolism (VTE) among survivors of childhood cancer and to identify risk factors for VTE to facilitate diagnosis and prevention. Methods The Childhood Cancer Survivor Study is a multi-institutional cohort of 24,355 5-year childhood cancer survivors (diagnosed between 1970 and 1999; median age at last follow-up, 28.7 years [range, 5.6 to 58.9 years]; median follow-up since diagnosis, 21.3 years [range, 5.0 to 39.2 years]) and 5,051 sibling participants. The primary end point was self-reported late (≥ 5 years after cancer diagnosis) VTE. Rate ratios (RRs) were estimated with multivariable piecewise exponential models. Results Late VTE incidence among survivors and siblings was 1.1 and 0.5 events per 1,000 person-years, respectively (RR, 2.2; 95% CI, 1.7 to 2.8), with 2.5 excess events per 100 survivors over 35 years. Among survivors, risk factors for VTE were female sex (RR, 1.3; 95% CI, 1.1 to 1.6), cisplatin (reference none; 1 to 199 mg/m2: RR, 3.0 [95% CI, 1.4 to 6.5]; 200 to 399 mg/m2: RR, 1.9 [95% CI, 1.0 to 3.6]; ≥ 400 mg/m2: RR, 2.0 [95% CI, 1.2 to 3.3]), l-asparaginase (RR, 1.3; 95% CI, 1.0 to 1.7), obesity or underweight (reference body mass index [BMI] 18.5 to 24.9 kg/m2; BMI ≥ 30.0 kg/m2: RR, 1.6 [95% CI, 1.2 to 2.0]; BMI < 18.5 kg/m2: RR, 2.4 [95% CI, 1.7 to 3.4]), and late cancer recurrence or subsequent malignant neoplasm (RR, 4.6; 95% CI, 3.6 to 5.8). Among lower-extremity osteosarcoma survivors, limb salvage (reference amputation; RR, 3.1; 95% CI, 1.2 to 7.5) and cisplatin 200 to 399 or ≥ 400 mg/m2 (reference none; RR, 4.0 [95% CI, 1.1 to 14.6] and 2.9 [95% CI, 1.1 to 8.0], respectively) were independently associated with late VTE. VTE was associated with increased risk for nonexternal cause late mortality (RR, 1.9; 95% CI, 1.6 to 2.3). Conclusion Childhood cancer survivors are at increased risk for VTE across their lifespan and a diagnosis of VTE increases mortality risk. Interventions that target potentially modifiable comorbidities, such as obesity, warrant consideration, with prophylaxis for high-risk survivors, including those treated with cisplatin and limb-sparing approaches.

Venous thromboembolism incidence in hematologic malignancies

Venous thromboembolism (VTE) remains a major cause of morbidity and mortality in patients with cancer. Although some very well validated scores delineate the risk of VTE by cancer subtype and other risk factors, hematologic malignancies are underrepresented in these models. This subgroup represents a unique entity that undergoes therapy that can be thrombogenic. The overall risk of VTE in patients with leukemia depends on the use of L-asparaginase treatment, older age, comorbidities and central venous catheters. Patients with acute promyelocytic leukemia are at particularly high risk of VTE but also have an increased risk of bleeding. Patients with aggressive lymphomas have a high incidence of VTE, roughly 10%. Patients with multiple myeloma at highest risk of VTE are those receiving immunomodulatory agents such as thalidomide or lenalidomide. Allogeneic stem cell transplantation carries a risk of thrombosis, particularly in patients developing graft versus host disease. This review summarizes the incidence of VTE in leukemia, lymphoma, myeloma and stem cell transplantation and provides practical guidance for preventing and managing VTE in patients with hematologic malignancies.

Mean platelet volume as a predictive marker for venous thromboembolism in patients treated for Hodgkin lymphoma

Mean platelet volume (MPV) is reported to be associated with the risk of venous thromboembolism (VTE) and mortality in patients with cancer. We sought to determine the association of MPV with symptomatic VTE occurrence in patients treated for newly diagnosed Hodgkin lymphoma (HL) and their outcomes. We retrospectively studied 167 consecutive adult patients treated with HL. During first-line treatment 12 (7.2%) patients developed VTE and 14 (8%) died within the observation period. The pre-chemotherapy values of MPV were significantly lower in VTE patients than those without (p=0.0343). Patients with MPV≤25^th percentile (6.8 fl) had an increased risk of VTE occurrence (p=0.0244). In multivariate analysis, MPV≤25^th percentile (OR 2.21; 95%CI 1.07-4.57, p=0.033), advanced stage (OR 2.08; 95%CI 1.06-4.07, p=0.033) and bulky disease (OR 2.23; 95%CI 1.16-4.31, p=0.016) were significant factors for developing VTE. Only the impact of MPV≤25^th percentile on VTE-free survival rates was found. VTE occurred in 43% (n=3) of the high-risk patients of the Thrombosis Lymphoma (ThroLy) score and in 17% (n=2) of the high-risk of the Khorana Risk Score (KRS). Neither the KRS nor the ThroLy score could identify patients at a high risk of VTE with a high degree of accuracy. We expanded the ThroLy score with the addition of the MPV≤25^th percentile to more accurately identify HL patients with a higher risk of VTE. Our study indicates that the pre-chemotherapy MPV value, while of no use as an overall prognosis predictor, may still represent a useful prognostic marker for a significant VTE risk especially when incorporated into VTE-risk assessment models.

Long-Term Incidence of Venous Thromboembolism in Cancer: The Scandinavian Thrombosis and Cancer Cohort

The risk of venous thromboembolism (VTE) in patients who survive the first years after a cancer diagnosis after the acute effects of disease and treatment in comparison to a similar background population has been sparsely investigated. The aim of the study was to investigate if incidence rates (IRs) of VTE differed in patients who were alive at least 2 years after a cancer diagnosis without VTE compared with cancer-free references in a population-based cohort study. The study entry was 2 years after a first cancer diagnosis. For each cancer-exposed subject, five reference subjects were identified within the cohort. The IRs were calculated as number of VTEs per 1,000 person years (×10 ^-3 p-y) in total and in distinct cancer types and corresponding reference subjects. Incidence rate ratios (IRRs) were calculated by Poisson's regression. During a mean follow-up of 5.3 years, 110 VTEs occurred among the 7,288 cancer-exposed subjects and 321 VTEs occurred among the 36,297 identified reference subjects. The IR of VTE was higher for cancer-exposed subjects compared with reference subjects, IRs 3.7 × 10 ^-3 p-y, 95% CI: 3.1 to 4.5 and 1.9 × 10 ^-3 p-y, 95% CI: 1.7 to 2.2, respectively. IRs of VTE in most solid cancer types declined to almost the same level as in the reference subjects 2 years after cancer diagnosis, but remained higher in hematological cancers, IRR 4.0, 95% CI: 2.0 to 7.8.

Epidemiology of venous thromboembolism in hematological cancers: The Scandinavian Thrombosis and Cancer (STAC) cohort

INTRODUCTION

Venous thromboembolism (VTE) is an important cause of morbidity and mortality in cancer patients, however the risk of VTE differs according to cancer type. Hematological cancers have varying phenotypes. Incidence rates (IR) of VTE in different hematological cancer types have not been investigated in a cancer-exposed subset of the general population.

METHODS

In a population-based cohort, we estimated incidence rates of VTE among patients with six subtypes of hematological cancer and among age and sex matched reference subjects.

RESULTS

During a mean follow-up of 4.8years, 30 objectively confirmed first-time symptomatic VTEs occurred among 838 subjects with hematological cancer. The IR of VTE was higher in all types of cancer except for indolent lymphoma but including chronic lymphocytic leukemia compared with reference subjects both during the first year after cancer diagnosis and 1-5years after diagnosis. IR of VTE for indolent lymphoma was not higher than controls.

CONCLUSION

The IRs of VTE were increased in all types of hematological cancer (including chronic lymphocytic leukemia) compared with reference subjects except indolent lymphomas.

Confounding in observational studies based on large health care databases: problems and potential solutions - a primer for the clinician

Population-based health care databases are a valuable tool for observational studies as they reflect daily medical practice for large and representative populations. A constant challenge in observational designs is, however, to rule out confounding, and the value of these databases for a given study question accordingly depends on completeness and validity of the information on confounding factors. In this article, we describe the types of potential confounding factors typically lacking in large health care databases and suggest strategies for confounding control when data on important confounders are unavailable. Using Danish health care databases as examples, we present the use of proxy measures for important confounders and the use of external adjustment. We also briefly discuss the potential value of active comparators, high-dimensional propensity scores, self-controlled designs, pseudorandomization, and the use of positive or negative controls.

Impact of Time-Varying Treatment Exposures on the Risk of Venous Thromboembolism in Multiple Myeloma

Multiple myeloma (MM) has one of the highest risks of venous thromboembolism (VTE) of all cancers due to pathologic changes and treatment-related exposures. This study assessed the one-year incidence of VTE in newly diagnosed MM and to determine the baseline and time-varying treatment-related factors associated with VTE risk in a U.S.-based cohort. MM patients were identified and age, gender, and baseline comorbidities were determined. Treatment-related exposures included thalidomide derivatives (IMIDs), proteasome inhibitors, cytotoxic chemotherapy, steroids, erythropoietin-stimulating agents (ESAs), stem cell transplants (SCT), hospitalizations, infection, and central venous catheters (CVC). Multiple statistical models were used including a baseline competing risks model, a time-varying exposure Cox proportional hazard (CPH) model, and a case-time-control analysis. The overall incidence of VTE was 107.2 per 1000 person-years with one-half of the VTEs occurring in the first 90 days. The baseline model showed that increasing age, heart failure, and hypertension were associated with one-year incidence of VTE. MM-specific IMID treatment had lower than expected associations with VTE based on prior literature. Instead, exposure to ESAs, SCT, CVC, and infection had higher associations. Based on these results, VTE risk in MM may be less straightforward than considering only chemotherapy exposures, and other treatment-related exposures should be considered to determine patient risk.

Incidence of venous thromboembolism in patients with non-Hodgkin lymphoma

INTRODUCTION

Patients with non-Hodgkin lymphoma (NHL) have an increased risk of venous thromboembolism (VTE). Current risk-prediction models classify NHL as a single entity. We aimed to quantify the difference in VTE risk in follicular lymphoma (FL) versus diffuse large B cell lymphoma (DLBCL).

METHODS

Using a prospective cohort study, we identified 2730 patients (2037 DLBCL; 693 FL) within the Veteran's Administration Central Cancer Registry. A competing risk model assessed the association between VTE risk and histology in the first year after NHL diagnosis. We assessed the effect of additional risk factors for VTE in NHL.

RESULTS

In univariate analysis, DLBCL was associated with increased risk of VTE compared to FL in the first year after diagnosis; this association was no longer significant in adjusted analysis (adjusted hazard ratio (aHR) 1.52; 95% CI 0.97-2.40). Major risk factors for VTE included history of VTE before NHL diagnosis (aHR 4.73, p≤0.0001) and time period during chemotherapy administration (aHR 7.60, p≤0.0001). Additional risk factors included: stage III/IV disease (p=0.02), BMI≥30 (p=0.02), B-symptoms (p=0.02), and doxorubicin (p=0.04). The cumulative incidence of VTE was highest in the period following diagnosis and decreased over time for both histologies.

CONCLUSION

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 (especially doxorubicin) and history of VTE. This knowledge can assist clinicians in identifying NHL patients at high risk for VTE.