Prognostic impact and risk factors of cancer-associated thrombosis events in stage-IV cancer patients treated with immune checkpoint inhibitors

Thromboembolism during immune checkpoint inhibitor therapy: frequency and risk factors

BACKGROUND

Thromboembolism (TE) is a well-known complication during chemotherapy in cancer patients. However, the risk of TE associated with immune checkpoint inhibitors (ICIs) is unknown. This study was performed to investigate the incidence of TE and associated risk factors in patients treated with ICIs.

METHODS

We conducted a retrospective chart survey of patients receiving at least one ICI at Shinshu University Hospital between September 2014 and October 2021. Age, sex, cancer type, body mass index, medical history, laboratory data at commencement of treatment, and medication data were obtained from electronic medical records. TE events (venous thromboembolism [VTE], arterial thromboembolism [ATE]) were identified after ICI initiation.

RESULTS

The study population consisted of 548 patients with a median age of 70.0 (19-89) years, 71.4% men, and a median follow-up of 15.1 months (range; 0.16-72.0 months). Nivolumab was the most commonly used ICI (45.8%), followed by pembrolizumab (23.9%), pembrolizumab plus anticancer drugs (7.8%), and nivolumab plus ipilimumab (5.1%). Thirty-eight cases of TE (6.9%) occurred (22 VTE, 16 ATE). Risk factors significantly associated with TE in multivariate logistic analysis were dyslipidemia (OR 2.44; 95% CI 1.17-5.09; p = 0.017), Khorana score ≥ 2 (HR 2.40; 95% CI 1.14-5.04; p = 0.021). Overall survival was not significantly different from patients without TE (p = 0.963).

CONCLUSION

These results suggested that the frequency of TE is higher than expected and should be considered and monitored in patients treated with ICIs.

Venous and Arterial Thromboembolism in Lung Cancer Patients: A Retrospective Analysis

Background: Patients with lung cancer face an increased incidence of venous (VTE) and arterial (ATE) thromboembolism. Risk factors for thrombosis remain unclear, particularly the impact of the use of immune checkpoint inhibitors (ICIs). We sought to compare the incidence of VTE and ATE in lung cancer patients receiving platinum-based therapy versus those receiving ICIs alone or in combination with chemotherapy and to validate the Khorana risk score for predicting VTE in the era of ICIs. Methods: A retrospective single-institution data analysis of 173 patients diagnosed with locally advanced or metastatic lung cancer at the Jena University hospital between 2015 and 2021. Results: The study revealed a high incidence of VTE (17.9%) and ATE (5.8%). The VTE risk was higher in patients diagnosed with adenocarcinoma (OR 0.29, 95% CI 0.09-0.93) than in patients with other histological types. A prior venous event was associated with an increased risk of recurrent VTE (OR 4.46, 95% CI 1.20-16.63). The incidence of thrombosis under first-line platinum-based chemotherapy did not differ from the incidence under ICIs (p = 0.19). There were no differences in the subgroup of patients who received ICIs alone or combined immunochemotherapy (p = 0.43). The Khorana score failed to predict the risk of VTE correctly. Conclusions: We did not find evidence supporting the theory that ICI therapy (alone or combined) increases the risk of thrombotic events. Adenocarcinoma and a prior history of VTE were strongly associated with an increased risk of VTE. Other scores for thrombotic risk assessment in lung cancer patients should be tested in prospective studies.

Platelet Parameters as Biomarkers for Thrombosis Risk in Cancer: A Systematic Review and Meta-analysis

Cancer-associated thrombosis (CAT) is a major cause of both morbidity and mortality in cancer patients. Platelet count has been investigated as a predictor of CAT in various settings while knowledge on platelet activation parameters is sparse. This report provides a systematic review and meta-analysis on available literature on associations between platelet count and/or function and arterial and venous thrombosis in adult cancer patients. The review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. PubMed and Embase were searched up to March 2022. The National Heart, Lung, and Blood Institute's tools were used for quality assessment. In total, 100 studies were included which investigated the association between CAT and platelet count (n = 90), platelet indices (n = 19), and platelet function/activation markers (n = 13) in patients with solid cancers (n = 61), hematological cancers (n = 17), or mixed cancer types (n = 22). Eighty-one studies had venous thrombosis as their outcome measure, while 4 had arterial thrombosis and 15 studies had both. We found significantly elevated odds ratio of 1.50 (95% confidence interval: 1.19-1.88) for thrombosis with higher platelet counts. We saw a tendency toward an association between markers of platelet activation in forms of mean platelet volume and soluble P selectin and both arterial and venous thrombosis. Only one study investigated dynamic platelet function using flow cytometry. In conclusion, platelet count is associated with CAT across different cancer types and settings. Platelet function or activation marker analysis may be valuable in assisting thrombosis risk assessment in cancer patients but is sparsely investigated so far.

Update on Thrombosis Risk in Patients with Cancer: Focus on Novel Anticancer Immunotherapies

Thromboembolic complications, including venous thromboembolism (VTE) and arterial thromboembolism (ATE), increase mortality and morbidity, and delay treatment in patients with cancer. Therefore, an increased understanding of underlying risk profiles, the identification of risk factors and predictive biomarkers, and ultimately the development of specific cardiovascular prevention strategies in patients with cancer is needed. Medical anticancer therapies have undergone a remarkable development in recent years with the advent of targeted and immunotherapeutic treatment options, including immune checkpoint inhibitors (ICI), chimeric antigen receptor (CAR) T-cell therapies and bispecific T-cell engagers (BiTEs). These developments have important implications for the accompanied risk of thromboembolic events in patients with cancer. First, the increased use of these highly effective therapies renders a growing proportion of patients with cancer at risk of thromboembolic events for a prolonged risk period due to an increase in patient survival despite advanced cancer stages. Second, potential direct cardiovascular toxicity and prothrombotic effect of novel anticancer immunotherapies are a matter of ongoing debate, with emerging reports suggesting a relevant risk of VTE and ATE associated with ICI, and relevant dysregulations of hemostasis in the frequently observed cytokine-release syndrome associated with BiTEs and CAR T-cell therapy. The aim of the present narrative review is to summarize the implications of the emerging use of anticancer immunotherapy for thromboembolic events in patients with cancer, and to provide an overview of available data on the rates and risk factors for VTE and ATE associated with ICI, CAR T-cell therapy, and BiTEs.

Risk Factors of Venous Thromboembolic Disease in Cancer Patients Treated with Immune Checkpoint Inhibitor

BACKGROUND

 Immune checkpoint inhibitors (ICIs) have revolutionized the management of cancers. The risk factors and pathophysiological mechanisms of venous thromboembolic events (VTEs) of this new therapeutic class are still to be specified.

METHODS

 The included patients had to have cancer and should be treated with ICI. Data analyzed included demographic data, biological data, and immune-related adverse events (IRAEs). We studied the prevalence of VTEs and the factors associated with VTEs.

RESULTS

 Of 374 patients on ICI, over a median follow-up period of 15.2 months, the number of VTE was 50 (13.4%). The majority of patients were treated for metastatic melanoma or nonsmall cell lung cancer. There was no difference in prevalence or survival between cancer types. Patients with combined therapy composed of nivolumab and ipilimumab had higher 1-year cumulative VTE occurrence (29.3% [95% confidence interval [CI]: 9.7; 44.6]) than patients with pembrolizumab (14.9%, [95%CI: 2.5; 25.8], p = 0.03) or nivolumab (9.1%, [95% CI: 5.0; 12.9], p < 0.01). The presence of IRAE was associated with a higher risk of VTE occurrence compared with patients without any IRAE (1-year VTE cumulative incidence: 17.42% [95% CI: 9.5; 24.65] vs. 9.46% [95% CI: 5.18; 13.55], p = 0.04). There was a higher risk of VTE in patients treated with the combination of nivolumab and ipilimumab (adjusted subdistribution hazard ratio [SHR]: 3.71 [95% CI: 1.74; 7.90], p < 0.001) and in patients with IRAE (adjusted SHR: 2.14 [95% CI: 1.22; 3.75], p < 0.01).

CONCLUSION

 The prevalence of VTE was 14.2% under ICIs. IRAE and combine treatment of nivolumab and ipilimumab were associated with VTE. The pathophysiological mechanisms are multiple and complex with a possible link to aberrant activation of the immune system.

Immune checkpoint inhibitor-associated thrombosis in patients with bladder and kidney cancer: a study of the Spanish Society of Medical Oncology (SEOM) thrombosis and cancer group

PURPOSE

Both venous and arterial thrombotic events (VTE/AT) can be associated with immune checkpoint inhibitors (ICI). However, there is a paucity of information apropos patients in routine clinical practice.

METHODS/PATIENTS

Retrospective, multicenter study promoted by the Thrombosis and Cancer Section of the Spanish Society of Medical Oncology (SEOM). Individuals with kidney or bladder cancer who initiated ICI between 01/01/2015 and 12/31/2020 were recruited. Minimum follow-up was 6 months (except in cases of demise). The primary objective was to calculate the incidence of ICI-associated VTE/AT and secondary objectives included to analyze their impact on survival and identify variables predictive of VTE/AT.

RESULTS

210 patients with kidney cancer were enrolled. The incidence of VTE/AT during follow-up (median 13 months) was 5.7%. Median overall survival (OS) was relatively lower among subjects with VTE/AT (16 months, 95% CI 0.01-34.2 vs. 27 months, 95% CI 22.6-31.4; p = 0.43). Multivariate analysis failed to reveal predictive variables for developing VTE/ AT. 197 patients with bladder were enrolled. There was a 9.1% incidence rate of VTE/AT during follow-up (median 8 months). Median OS was somewhat higher in patients with VTE/AT (28 months, 95% CI 18.4-37.6 vs 25 months, 95% CI 20.7-29.3; p = 0.821). Serum albumin levels < 3.5 g/dl were predictive of VTE/ AT (p < 0.05).

CONCLUSIONS

There appears to be no association between developing VTE/AT and ICI use in patients with renal or bladder cancer. Serum albumin levels are a predictive factor in individuals with bladder cancer.

Immune Checkpoint Inhibitors-Associated Thrombosis: Incidence, Risk Factors and Management

Immune checkpoint inhibitors (ICIs) target programmed cell death (PD) 1 receptor and its ligand PD-L1, and have become an integral part of treatment regimens in many cancers including lung cancer, renal cell carcinoma, melanoma, and more. Cancer is associated with a significantly increased risk of venous thromboembolism compared to non-cancer patients, and the risks increase further with anticancer therapies including ICIs. Cancer-associated thrombosis can lead to hospitalizations, delayed cancer treatment, and mortality. While thrombosis was not reported as a major complication in initial clinical trials leading to the approval of ICIs, emerging evidence from post-marketing studies revealed concerning risks of thrombosis in patients receiving ICIs. However, results remained heterogenous given differences in study designs and populations. Recent studies also showed that C-reactive protein dynamics might be an easily accessible biomarker for thrombosis and disease response in this population. In addition, early findings indicated that a commonly used anticoagulant for cancer-associated thrombosis, factor Xa inhibitors, might have potential synergistic antitumor effects when combined with ICIs. Herein we will review the current literature on the incidence, risk factors, and management of thrombosis in patients with cancer receiving ICIs. We aim to provide valuable information for clinicians in managing these patients.

Characteristics and Outcomes of Cancer Patients With Venous Thromboembolic Events After Treatment With Immune Checkpoint Inhibitors

OBJECTIVE

This study aimed to describe the clinical characteristics and outcomes of patients with venous thromboembolism (VTE) after Immune checkpoint inhibitors (ICI), focusing on patients with gastrointestinal (GI) immune-related adverse events (irAE).

METHODS

In this retrospective, single-center study, we report the clinical outcomes of adult cancer patients who developed a VTE within 2 years of ICI initiation. Patients were excluded if alternate causes of VTE were present apart from malignancy and cancer therapy. The cohort was classified into those with GI-irAE, non-GI-irAE, and no irAE. A control group with ICI exposure without irAE and VTE was selected for comparative analysis.

RESULTS

Of all ICI-treated patients, 1891 (17.2%) were diagnosed with VTE. In all, 501 (4.6%) had no etiology for VTE aside from malignancy and cancer therapy. Of these, 137 patients were included and classified as: 44 GI-irAE, 42 non-GI-irAE, and 51 no irAE. Chemotherapy within 6 months of ICI therapy was associated with increased VTE risk. There was no difference in the clinical course between those exposed to chemotherapy versus ICI therapy alone, time from ICI initiation to VTE, and VTE type, recurrence, or related hospitalization. While there was no difference in VTE-related mortality, the GI-irAE group was associated with lower all-cause mortality and superior overall survival.

CONCLUSION

Combined ICI and chemotherapy use increased VTE risk. There is a similar disease course of VTE after ICI exposure, regardless of other irAEs. Co-existing GI-irAE with VTE is associated with superior overall survival. Prospective studies are needed to evaluate the relationship between ICI therapy and VTE and irAE impact on VTE outcomes.

Associations Between Immune-Related Venous Thromboembolism and Efficacy of Immune Checkpoint Inhibitors: A Systematic Review and Meta-Analysis

This study aims to summarize the available data and determine if the presence of venous thromboembolism (VTE) immune-related adverse event (irAE) in patients with immune checkpoint inhibitor (ICI) therapy is associated with improved treatment efficacy and clinical outcomes, which in turn was used to help optimize patient selection for anticoagulation therapy and inform rational treatment strategies for overcoming the mechanisms of ICI resistance. PubMed, Embase, Web of Science, and Cochrane Library were searched up to March 18, 2023, for studies assessing the relationship between VTE irAE development during ICI therapy and cancer outcomes. Seven primary articles with a total of 4437 patients were included in the overall survival (OS) meta-analysis. Patients with VTE had a significant increase in overall mortality compared to patients without VTE in adjusted hazard ratios (HRs 1.36, 95% confidence interval [CI] 1.06-1.75, P  =  .02). In the studies where immortal time bias (ITB) was accounted for, patients with VTE irAE also had poor OS than those without. HR and the corresponding 95% CI values in the non-ITB group were 2.53 (1.75-3.66, P < .00001) with low heterogeneity (P  =  .17, I2  =  48%) and 1.21 (1.06-1.37, P  =  .004) in the ITB group with no heterogeneity (P  =  .95, I2  =  0%), respectively. Despite the heterogeneity identified, the evidence does suggest that VTE irAE occurrence could be served as a prognostic indicator, with higher frequencies of occurrence associated with poorer OS. However, the fundamental role of this association with clinical consequences should be further investigated in large cohorts and clinical trials.

The Khorana score and venous and arterial thrombosis in patients with cancer treated with immune checkpoint inhibitors: A Danish cohort study

BACKGROUND

Thrombosis is common among patients with cancer. Primary thromboprophylaxis guided by the Khorana score is endorsed by guidelines but recommendations rely mainly on data from patients treated with chemotherapy.

OBJECTIVES

To explore if the Khorana score could risk stratify patients with cancer treated with immune checkpoint inhibitors according to risk of venous and arterial thrombosis.

PATIENTS/METHODS

The study population and Khorana score were defined using administrative Danish health registries. The primary outcome was 6-month risk of venous thromboembolism after initiation of checkpoint inhibitor treatment. Secondary outcomes were arterial thrombosis and any thromboembolic event. Death was considered a competing risk event.

RESULTS

Among 3946 patients with cancer initiating checkpoint inhibitor treatment without other indications for anticoagulation, the overall 6-month incidence of venous thromboembolism was 2.6% (95% confidence interval [CI]: 2.1-3.1). Risks were 2.1% (95% CI: 1.5-3.0), 2.6% (95% CI: 2.0-3.4), and 3.7% (95% CI: 2.1-5.9) in low (score 0), intermediate (score 1-2), and high risk (score ≥3) Khorana categories, respectively. Among patients eligible for primary thromboprophylaxis according to guidelines (Khorana score ≥2), risk of venous thromboembolism was 4.1% (95% CI: 3.1-5.4). Higher Khorana risk category was also associated with higher 6-month risk of both arterial thrombosis and any thromboembolic events.

CONCLUSIONS

The Khorana score was able to risk stratify patients with cancer treated with immune checkpoint inhibitors according to 6-month risk of thromboembolic events. Risks of venous thromboembolism were lower than in randomized thromboprophylaxis trials, thus questioning the absolute benefit of routine primary thromboprophylaxis in an unselected population of patients treated with immune checkpoint inhibitors.

Risk of Thromboembolic Events in Cancer Patients Treated with Immune Checkpoint Inhibitors: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

 The association between immune checkpoint inhibitors (ICIs) and thromboembolic events (TEEs) remains controversial.

OBJECTIVE

 The goal of this study was to assess the risk of major TEEs associated with ICIs.

METHODS

 We explored ICI-related TEEs in randomized controlled trials available in ClinicalTrials.gov and electronic databases up to June 30, 2021. Meta-analysis was performed by using Peto odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

 A total of 61 studies were included. Patients treated with ICIs had a similar risk of venous thromboembolism (VTE) but a significantly increased risk of arterial thromboembolism (ATE) (Peto OR: 1.58 [95% CI: 1.21-2.06]) compared with non-ICI regimens. Stratified by different regimens, only PD-L1 (programmed cell death ligand 1) inhibitors showed a significant increase in ATE (Peto OR: 2.07 [95% CI: 1.26-3.38]). The incidence of VTE was higher in PD-1/PD-L1 inhibitor and CTLA-4 (cytotoxic T lymphocyte antigen 4) inhibitor combination therapies compared with monotherapies (Peto OR: 2.23 [95% CI: 1.47-3.37]). Stratified by tumor, for pulmonary embolism (PE) and cerebral ATE, the statistically significant results were only seen in lung cancer patients (Peto OR: 1.42 [95% CI: 1.02-1.97]; Peto OR: 2.10 [1.07-4.12]), and for myocardial infarction, the statistically significant result was only seen in other tumor types (Peto OR: 2.66 [95% CI: 1.68-4.20], p < 0.0001).

CONCLUSION

 There was no significant increase in the overall risk of VTE in patients treated with ICIs; however, special attention should be given to the risk of VTE in PD-1/PD-L1 inhibitor and CTLA-4 inhibitor combination therapy and PE in lung cancer patients. PD-L1 inhibitors were associated with a significant increase in ATE.

Immune checkpoint inhibitors-associated thrombosis in patients with lung cancer and melanoma: a study of the Spanish society of medical oncology (SEOM) thrombosis and cancer group

Purpose

Immune Checkpoint Inhibitors (ICI) can be associated with thrombotic events, both venous and arterial (VTE/AT). However, there is a paucity of information regarding patients in routine clinical practice.

Methods/patients

Retrospective, multicenter study promoted by the Thrombosis and Cancer Section of the Spanish Society of Medical Oncology (SEOM). Patients with melanoma and lung cancer who initiated ICI between 01/01/2015 and 31/12/2019 were recruited. Minimum follow-up was 6 months (unless it was not possible because of death). The primary objective was to calculate the incidence of ICI-associated VTE/AT and the secondary objectives included to analyze its impact on survival and to identify predictor variables for VTE/AT.

Results

665 patients with lung cancer were enrolled. The incidence of VTE/AT during follow-up was 8.4%. Median overall survival (OS) was lower in the VTE/AT group (12 months 95% CI 4.84–19.16 vs. 19 months 95% CI 16.11–21.9; p = 0.0049). Neutrophil/lymphocyte ratio (NLR) and anemia upon initiation of IT, as well as a history of thrombosis between cancer diagnosis and the start of ICI, were predictive variables for developing of VTE/AT (p < 0.05). 291 patients with melanoma were enrolled. There was a 5.8% incidence rate of VTE/AT during follow-up. Median OS was lower in the VTE/AT group (10 months 95% CI 0.0–20.27 vs. 29 months 95% CI 19.58–36.42; p = 0.034). NLR and lactate dehydrogenase (LDH) at the beginning of ICI were predictor variables for VTE/AT (p < 0.05).

Conclusions

ICI increases the risk of VTE/AT in patients with lung cancer and melanoma, which impact OS.

Cardiovascular disease and malignant melanoma

In the last decade, systemic therapies such as immune checkpoint inhibitors and BRAF-MEK inhibitors have improved the prognosis of high-risk and advanced melanoma. With improved survival, melanoma survivorship is increasingly important, particularly in patients who have a good prognosis or are diagnosed at a younger age. It is increasingly recognized that cancer and its treatment is associated with increased cardiovascular morbidity and mortality. Indeed, data from observational studies and meta-analyses of randomized controls trials in melanoma show that systemic therapies may be associated with cardiac toxicities, such as myocardial infarction, heart failure, myocarditis and stroke. Our review will discuss cardiovascular disease and risk factors in the context of melanoma and outline the importance of cardiovascular risk modification in this population.

Old is new again: emergence of thromboembolic complications in cancer patients on immunotherapy

Cancer immunotherapy has emerged as one of the most important new treatments for cancer in many years, moving rapidly to front-line therapy for several cancers. Cancer immunotherapy is based on treatment with immune checkpoint inhibitors (ICI), which are monoclonal antibodies directed toward immunoregulatory proteins including PD-1, PD-L1 and CTLA-4. ICI inhibit interactions between these proteins and their ligands, disabling physiologic immune regulatory networks and enhancing anti-tumor immunity. However, since the immune response cannot be directed specifically to the tumor, ICI are associated with immune-related adverse events (irAEs) resulting from immune-mediated attack of normal tissues. We and others have reported a high incidence of thrombosis in patients treated with ICI, which may approach 20%. Given the rapidly increasing use of ICIs, it is clear that ICI-Associated Thrombosis (IAT) is a major emerging clinical problem. However, there is a remarkable knowledge gap concerning mechanisms of IAT. IAT may be a composite irAE resulting from activation of blood and vascular cells, leading to thromboinflammation. Cancer itself is an inflammatory disorder, and inducing further inflammation through ICI administration may stimulate procoagulant activity by multiple cell types. Moreover, some blood and vascular cells express ICI target proteins. Here, we review the results of several studies describing the clinical manifestations of IAT, as well as our recent studies demonstrating that elevated levels of myeloid derived suppressor cells and inflammatory cytokines may serve as biomarkers of IAT. It is hoped that the concepts reviewed here may stimulate further research into this important clinical problem.

Incidence of venous thromboembolism and discriminating capacity of Khorana score in lung cancer patients treated with immune checkpoint inhibitors

Venous-thromboembolism (VTE) is increased in lung cancer patients (LCP) treated with immune-checkpoint inhibitors (ICIs) but risk factors are not identified and the Khorana Score (KS) is not validated. To assess VTE incidence and its clinical impact, to investigate potential clinical risk factors and KS performance in LCP. Retrospective analysis of LCP initiating ICIs treatment between June 2015 and November 2020 in a for-profit cancer center. 481 patients were included: 62% adenocarcinoma, 70% PDL1 + , 86% stage-IV-disease. Over a median follow-up of 9.8 months, 47 VTE were observed: 28 pulmonary embolisms, 15 deep venous thromboses (distal n = 9, proximal n = 6), 3 inferior vena cava thromboses, 1 other VTE, no superficial or digestive vein thrombosis. Median time from ICIs' initiation to VTE was 180 (11-1277) days. Overall survival was significantly lower in patients who experienced VTE (42.5 vs. 86.8 months, p = 0.006). In univariate analysis patients VTE was more frequent in metastatic patients (11.1% vs. 1.5%, p = 0.015) and lower in those treated with durvalumab (1.9% vs. 9.6%, p = 0.046). Logistic regression analysis showed that non-metastatic status (OR 0.13; 0.02-0.95, p = 0.04) and BMI (OR 1.07; 1.01-1.14, p = 0.028) were associated with VTE. The rate of VTE was the same in patients with a KS < or ≥ 2 (10.2% vs. 9.3%, p = 0.87). ICIs-treated LCP are at high risk of thromboembolism. VTE has a negative impact on survival. KS does not perform well in LCP. It is important to identify which VTE prediction models are available to be used in adult ambulatory lung cancer patients.

Cancer-associated venous thromboembolism

Cancer-associated thrombosis (including venous thromboembolism (VTE) and arterial events) is highly consequential for patients with cancer and is associated with worsened survival. Despite substantial improvements in cancer treatment, the risk of VTE has increased in recent years; VTE rates additionally depend on the type of cancer (with pancreas, stomach and primary brain tumours having the highest risk) as well as on individual patient's and cancer treatment factors. Multiple cancer-specific mechanisms of VTE have been identified and can be classified as mechanisms in which the tumour expresses proteins that alter host systems, such as levels of platelets and leukocytes, and in which the tumour expresses procoagulant proteins released into the circulation that directly activate the coagulation cascade or platelets, such as tissue factor and podoplanin, respectively. As signs and symptoms of VTE may be non-specific, diagnosis requires clinical assessment, evaluation of pre-test probability, and objective diagnostic testing with ultrasonography or CT. Risk assessment tools have been validated to identify patients at risk of VTE. Primary prevention of VTE (thromboprophylaxis) has long been recommended in the inpatient and post-surgical settings, and is now an option in the outpatient setting for individuals with high-risk cancer. Anticoagulant therapy is the cornerstone of therapy, with low molecular weight heparin or newer options such as direct oral anticoagulants. Personalized treatment incorporating risk of bleeding and patient preferences is essential, especially as a diagnosis of VTE is often considered by patients even more distressing than their cancer diagnosis, and can severely affect the quality of life. Future research should focus on current knowledge gaps including optimizing risk assessment tools, biomarker discovery, next-generation anticoagulant development and implementation science.

Risk Factors, Incidence, and Prognosis of Thromboembolism in Cancer Patients Treated With Immune Checkpoint Inhibitors

In recent years, immune checkpoint inhibitors (ICIs) have become the standard treatment option for tumors. With the widespread application of ICIs, immune-related adverse events (irAEs) have gradually attracted the attention of researchers. Owing to the characteristics of ICIs, irAEs can affect each organ of the human body. Thromboembolism is uncommon in cancer patients receiving ICIs, but it may affect their survival. Most thromboembolic events do not cause serious effects after early prediction and treatment, but life-threatening toxic reactions are also observed. This condition should not be ignored because of vague and atypical symptoms, which make early diagnosis more challenging. This article focuses on the high-risk factors, underlying mechanisms, incidence, and prognosis of thromboembolism in patients using ICIs and briefly describes the intervention and treatment measures. This information would allow patients to effectively manage the side effects of thromboembolism during Immune checkpoint inhibitors treatment, ensuring the efficacy of ICIs and reducing mortality.

Thrombotic Complications Associated with Immune Checkpoint Inhibitors

Simple Summary

Patients with cancer commonly develop blood clots, which can cause issues including hospitalizations and complications and can affect cancer treatments. Cancer therapies can be one of the reasons for blood clots. A type of cancer therapy called “immune checkpoint inhibitors” has been used more and more often in recent years for different types of cancer. Recent reports revealed an increasing concern of blood clots related to immune checkpoint inhibitors. In this review, we will summarize data from the available studies and discuss the rates, risk factors, prevention, and treatment strategies for blood clots related to immune checkpoint inhibitors.

Abstract

Thromboembolism is a common complication in patients with cancer and is associated with significant morbidity and mortality. Anticancer treatment is a known risk factor of cancer-associated thrombosis. Immune checkpoint inhibitors have become a mainstay of treatment in various cancers. Both venous and arterial thrombosis have been increasingly reported as adverse events associated with immune checkpoint inhibitors in recent studies, with a cumulative incidence of venous thrombosis to be 5–8% at 6 months and over 10% at 12 months. Additionally, rates of approximately 1–5% for arterial thrombosis were reported at 12 months. Data also showed an association of thromboembolism with adverse survival. Many pertinent clinical questions in this population deserve further investigation, including the risks of thrombosis associated with immune checkpoint inhibitors as compared to those with traditional systemic therapy, associated risk factors, and the optimal prevention and treatment strategies. In this review, we synthesize data from available literature, provide relevant information for clinicians and potential future directions for research.