Diagnosing cancer-associated ischemic stroke: A systematic review of hematological biomarkers

BACKGROUND AND AIM

Patients suffering from cancer are reported to have an increased risk of ischemic stroke (IS). We aimed to identify cancer-associated biomarkers found to differentiate between IS associated with cancer from those not associated with cancer.

SUMMARY OF REVIEW

We performed a systematic search of PubMed and EMBASE databases according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The study is reported in PROSPERO (#CRD42022355129). In total, 5563 papers were screened, of which 49 papers were included. Seven biomarkers were identified which had the potential to differentiate between patients who had cancer or stroke or both conditions. D-dimer was the most frequently monitored biomarker, and high levels were significantly associated with cancer-related strokes in (42/44) studies. Fibrinogen was significantly associated with cancer-related strokes in 11/27 studies. A higher level of C-reactive protein, investigated in 19 studies, was associated with cancer-related strokes, but conclusive multivariate analysis was not performed. Finally, the four cancer-associated antigens CA125, CA153, CA199, and carcinoembryonic antigen were only reported on in three to six studies, respectively. These studies all originated from the Guangxi province in China. CA125 was associated with an increased risk of IS in four of six studies.

CONCLUSION

Increased D-dimer seems associated with cancer-related IS. CRP may also be a candidate as a cancer-associated stroke biomarker, but this requires further verification. Fibrinogen and the more specific cancer biomarkers have not yet been proven helpful for detecting cancer-related strokes.

Systematic review and meta-analysis of studies comparing baseline D-dimer level in stroke patients with or without cancer: Strength of current evidence

Objectives

D-dimer levels are increased in stroke and cancer. Cancer patients are at a higher risk of stroke. However, the evidence is unclear if high D-dimer in stroke patients can suggest the diagnosis of concomitant cancer or the development of stroke in a cancer patient. The objective is to assess the evidence available on the baseline D-dimer level in stroke patients with and without cancer.

Materials and Methods

We conducted the systematic review and meta-analysis using the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. We searched PUBMED, Cochrane, ScienceDirect, and Scopus for potentially eligible articles published till June 2023. All the review steps were iterative and done independently by two reviewers. The Newcastle-Ottawa scale tool was used to assess the quality of included studies for case control and cohort studies and the Agency for Healthcare Research and Quality tool for cross-sectional studies. The qualitative synthesis is presented narratively, and quantitative synthesis is shown in the forest plot using the random effects model. I2 of more than 60% was considered as high heterogeneity.

Results

The searches from all the databases yielded 495 articles. After the study selection process, six papers were found eligible for inclusion in the qualitative and quantitative synthesis. In the present systematic review, 2651 patients with ischemic infarcts are included of which 404 (13.97%) patients had active cancer while 2247 (86.02%) did not. The studies included were of high quality and low risk of bias. There were significantly higher baseline D-dimer levels in stroke patients with cancer than in non-cancer patients with a mean difference of 4.84 (3.07-6.60) P < 0.00001.

Conclusion

D-dimer is a simple and relatively non-expensive biomarker that is increased to significant levels in stroke patients, who have cancer and therefore may be a tool to predict through screening for active or occult cancer in stroke patients.

Cancer and Embolic Stroke of Undetermined Source

One-quarter to one-third of ischemic strokes have no established mechanism after standard diagnostic evaluation and are classified as embolic stroke of undetermined source (ESUS). Failure of randomized trials to demonstrate a benefit of direct oral anticoagulants over aspirin for the treatment of ESUS as a single homogeneous entity has led to renewed interest by stroke experts to divide ESUS into subgroups. Emerging data suggest that active cancer, which is present in 5% to 10% of patients with ESUS, is a distinct and important subgroup of ESUS with unique clinical characteristics, underlying pathophysiologies, and treatment and prognostic considerations. Furthermore, the prevalence of cancer-related ESUS is expected to increase as patients with cancer, even those with distant metastases, survive longer due to improvements in cancer treatments. In this topical review, we examine the epidemiological link between ESUS and cancer, the clinical features and potential mechanistic underpinnings of ESUS with cancer (with a focus on novel biomarkers and their relationship to recurrent stroke and other thromboembolic events), and the potential treatment strategies for cancer-related ESUS. We include a critical appraisal of existing data and ongoing or planned clinical trials of different antithrombotic approaches. As cancer-related ESUS is a dynamic disease with variable course, we recommend close collaboration between neurologists and oncologists to develop individualized management plans.

Frequency and predictors of occult cancer in ischemic stroke: A systematic review and meta-analysis

BACKGROUND

The optimal approach for cancer screening after an ischemic stroke remains unclear.

AIMS

We sought to summarize the existing evidence regarding the frequency and predictors of cancer after an ischemic stroke.

SUMMARY OF REVIEW

We searched seven databases from January 1980 to September 2019 for articles reporting malignant tumors and myeloproliferative neoplasms diagnosed after an ischemic stroke (PROSPERO protocol: CRD42019132455). We screened 15,400 records and included 51 articles. The pooled cumulative incidence of cancer within one year after an ischemic stroke was 13.6 per thousand (95% confidence interval [CI], 5.6-24.8), higher in studies focusing on cryptogenic stroke (62.0 per thousand; 95% CI, 13.6-139.3 vs 9.6 per thousand; 95% CI, 4.0-17.3; p = 0.02) and those reporting cancer screening (39.2 per thousand; 95% CI, 16.4-70.6 vs 7.2 per thousand; 95% CI, 2.5-14.1; p = 0.003). Incidence of cancer after stroke was generally higher compared to people without stroke. Most cases were diagnosed within the first few months after stroke. Several predictors of cancer were identified, namely older age, smoking, and involvement of multiple vascular territories as well as elevated C-reactive protein and d-dimers.

CONCLUSIONS

The frequency of incident cancer after an ischemic stroke is low, but higher in cryptogenic stroke and after cancer screening. Several predictors may increase the yield of cancer screening after an ischemic stroke. The pooled incidence of post-stroke cancer is likely underestimated, and larger studies with systematic assessment of cancer after stroke are needed to produce more precise and valid estimates.

Ischemic stroke: A paradoxical manifestation of cancer

INTRODUCTION

Approximately 5-10 % of the patients with cryptogenic stroke have an underlying malignancy. Stroke as a complication of cancer increases the morbidity and mortality among cancer patients, leading to increased disability and healthcare costs.

OBJECTIVE

To provide elements to guide physicians for when to suspect and evaluate for cancer in stroke patients.

DEVELOPMENT

We performed a narrative review, portrayed in a question-answer format, to report relevant aspects of cancer stroke patients in the clinical practice and provide a guide based on the state-of-the-art literature. Conventional stroke mechanisms are only found in a fraction of patients with cancer. Although cardiovascular risk factors play an important role in both cancer and stroke pathogenesis, the recognition of more specific cancer-associated risk factors raises clinical suspicion for occult malignancy. We also expose the main type location and histology of tumors that are most commonly associated with stroke as well as potential blood biomarkers and current treatment considerations in the scenario of cancer associated stroke.

CONCLUSION

Subjects with active cancer are a patient population at increased risk for developing an ischemic stroke. Cryptogenic stroke patients have a higher risk of cancer diagnosis in the following 6-12 months. We recommend a multidisciplinary approach considering the high probability of a hidden malignancy and running a comprehensive evaluation including neurologic imaging, serological biomarkers and tight follow up.

Stroke Classification: Critical Role of Unusually Large von Willebrand Factor Multimers and Tissue Factor on Clinical Phenotypes Based on Novel "Two-Path Unifying Theory" of Hemostasis

Stroke is a hemostatic disease associated with thrombosis/hemorrhage caused by intracranial vascular injury with spectrum of clinical phenotypes and variable prognostic outcomes. The genesis of different phenotypes of stroke is poorly understood due to our incomplete understanding of hemostasis and thrombosis. These shortcomings have handicapped properly recognizing each specific stroke syndrome and contributed to controversy in selecting therapeutic agents. Treatment recommendation for stroke syndromes has been exclusively derived from the result of laborious and expensive clinical trials. According to newly proposed "two-path unifying theory" of in vivo hemostasis, intracranial vascular injury would yield several unique stroke syndromes triggered by 3 distinctly different thrombogenetic mechanisms depending upon level of intracranial intravascular injury and character of formed blood clots. Five major phenotypes of stroke occur via thrombogenetic paths: (1) transient ischemic attack due to focal endothelial damage limited to endothelial cells (ECs), (2) acute ischemic stroke due to localized ECs and subendothelial tissue (SET) damage extending up to the outer vascular wall, (3) thrombo-hemorrhagic stroke due to localized vascular damage involving ECs and SET and extending beyond SET to extravascular tissue, (4) acute hemorrhagic stroke due to major localized intracranial hemorrhage/hematoma into the brain tissue or space between the coverings of the brain associated with vascular anomaly or obtuse trauma, and (5) encephalopathic stroke due to disseminated endotheliopathy leading to microthrombosis within the brain. New classification of stroke phenotypes would assist in selecting rational therapeutic regimen for each stroke syndrome and designing clinical trials to improve clinical outcome.

The Role of Pulmonary Veins in Cancer Progression from a Computed Tomography Viewpoint

Background. We studied the role of pulmonary veins in cancer progression using computed tomography (CT) scans. Methods. We obtained data from 260 patients with pulmonary vein obstruction syndrome (PVOS). We used CT scans to investigate pulmonary lesions in relation to pulmonary veins. We divided the lesions into central and peripheral lesions by their anatomical location: in the lung parenchymal tissue or pulmonary vein; in the superior or inferior pulmonary vein; and by unilateral or bilateral presence in the lungs. Results. Of the 260 PVOS patients, 226 (87%) had central lesions, 231 (89%) had peripheral lesions, and 190 (75%) had mixed central and peripheral lesions. Among the 226 central lesions, 93% had lesions within the superior pulmonary vein, either bilaterally or unilaterally. Among the 231 peripheral lesions, 65% involved bilateral lungs, 70% involved lesions within the inferior pulmonary veins, and 23% had obvious metastatic extensions into the left atrium. All patients exhibited nodules within their pulmonary veins. The predeath status included respiratory failure (40%) and loss of consciousness (60%). Conclusion. CT scans play an important role in following tumor progression within pulmonary veins. Besides respiratory distress, PVOS cancer cells entering centrally can result in cardiac and cerebral events and loss of consciousness or can metastasize peripherally from the pulmonary veins to the lungs.

Pulmonary Venous Obstruction in Cancer Patients

Background. We study the clinical significance and management of pulmonary venous obstruction in cancer patients. Methods. We conducted a prospective cohort study to characterize the syndrome that we term “pulmonary vein obstruction syndrome” (PVOS) between January 2005 and March 2014. The criteria for inclusion were (1) episodes of shortness of breath; (2) chest X-ray showing abnormal pulmonary hilum shadow with or without presence of pulmonary edema and/or pleural effusion; (3) CT scan demonstrating pulmonary vein thrombosis/tumor with or without tumor around the vein. Results. Two hundred and twenty-two patients developed PVOS. Shortness of breath was the main symptom, which was aggravated by chemotherapy in 28 (13%), and medical/surgical procedures in 21 (9%) and showed diurnal change in intensity in 32 (14%). Chest X-rays all revealed abnormal pulmonary hilum shadows and presence of pulmonary edema in 194 (87%) and pleural effusion in 192 (86%). CT scans all showed pulmonary vein thrombosis/tumor (100%) and surrounding the pulmonary veins by tumor lesions in 140 patients (63%). PVOS was treated with low molecular weight heparin in combination with dexamethasone, and 66% of patients got clinical/image improvement. Conclusion. Physicians should be alert to PVOS when shortness of breath occurs and chest X-ray reveals abnormal pulmonary hilum shadows.

Unusually Located Stroke After Chemotherapy in Testicular Germ Cell Tumors

Testicular cancer is a type of malignancy that affects young adults and has high rates of cure; however, as any malignancy, it is associated with an increased risk of ischemic or hemorrhagic cerebrovascular disease, given the systemic tumor effects or side effects of chemotherapy, which in turn increases morbidity, functional impairment, and additional risk of early death.

Ischaemic stroke as initial presentation of systemic malignancy

Ischaemic stroke as the initial presentation of systemic malignancy is reported infrequently and is characterised by ischaemic lesions that exceed the vascular territory of a single vessel. There is also a high rate of early stroke recurrence. Several pathophysiological mechanisms are known to cause cerebrovascular complications in malignancies, as a direct effect of the tumour, paraneoplastic or even of the tumour treatment itself. Prognosis is reportedly poor, treatment is symptomatic and at best anecdotal. We present a case report and available literature.

Stroke patients with a past history of cancer are at increased risk of recurrent stroke and cardiovascular mortality

BACKGROUND AND PURPOSE

Cancer patients are at increased risk of cardiovascular and cerebrovascular events. It is unclear whether cancer confers any additional risk for recurrent stroke or cardiovascular mortality after stroke.

METHODS

This was a single center, observational study of 1,105 consecutive Chinese ischemic stroke patients recruited from a large stroke rehabilitation unit based in Hong Kong. We sought to determine whether patients with cancer are at higher risk of recurrent stroke and cardiovascular mortality.

RESULTS

Amongst 1,105 patients, 58 patients (5.2%) had cancer, of whom 74% were in remission. After a mean follow-up of 76 ± 18 months, 241 patients developed a recurrent stroke: 22 in patients with cancer (38%, annual incidence 13.94%/year), substantially more than those without cancer (21%, 4.65%/year) (p<0.01). In a Cox regression model, cancer, age and atrial fibrillation were the 3 independent predictors of recurrent stroke with a hazard ratio (HR) of 2.42 (95% confidence interval (CI): 1.54-3.80), 1.01 (1.00-1.03) and 1.35 (1.01-1.82) respectively. Likewise, patients with cancer had a higher cardiovascular mortality compared with those without cancer (4.30%/year vs. 2.35%/year, p = 0.08). In Cox regression analysis, cancer (HR: 2.08, 95% CI: 1.08-4.02), age (HR: 1.04, 95% CI 1.02-1.06), heart failure (HR: 3.06, 95% CI 1.72-5.47) and significant carotid atherosclerosis (HR: 1.55, 95% CI 1.02-2.36) were independent predictors for cardiovascular mortality.

CONCLUSIONS

Stroke patients with a past history of cancer are at increased risk of recurrent stroke and cardiovascular mortality.

Predictive value of plasma (D)-dimer levels for cancer-related stroke: a 3-year retrospective study

BACKGROUND

Cerebrovascular disease is the second leading cause of central nervous system pathology in cancer patients. Cancer-associated hypercoagulation plays an important role in cancer-related stroke. The present study aims to test whether plasma d-dimer levels could predict comorbid malignancy in patients with ischemic stroke.

METHODS

Five hundred sixteen stroke patients with measured d-dimer levels and who were consecutively admitted to our stroke center from 2009 to 2012 were included. Cancer status was determined by medical chart, and 59 patients were identified to have active cancer. An additional 48 cancer patients with stroke were identified from the hospital database. Several d-dimer cutoff levels were used to predict cancer-related stroke.

RESULTS

Stroke patients with active cancer had significantly higher d-dimer levels than those without cancer (P < .001). The average d-dimer level in stroke patients without cancer was .66 ± 1.83 mg/L, whereas the levels for active cancer patients from the stroke center and hospital database were 5.70 ± 9.63 mg/L and 10.47 ± 12.31 mg/L, respectively. When using d-dimer of .55 mg/L or more and multiple territory infarctions as criteria, the specificity and positive predictive value (PPV) for cancer-related stroke were 99.7% and 92.9%, respectively. When using d-dimer of 5.5 mg/L or more as the cutoff value, the test had a high specificity and PPV regardless the brain magnetic resonance imaging (MRI) findings. Six stroke patients fitting our criteria were confirmed to have occult malignancy after comprehensive cancer survey.

CONCLUSIONS

Extraordinary high d-dimer levels or combining d-dimer and MRI findings may be used as a screening tool to detect malignancy in stroke patients.