Multivariate analysis of brain metabolism reveals chemotherapy effects on prefrontal cerebellar system when related to dorsal attention network

The remodeling of metabolic brain pattern in patients with extracranial diffuse large B-cell lymphoma

BACKGROUND

Owing to the advances in diagnosis and therapy, survival or remission rates for lymphoma have improved prominently. Apart from the lymphoma- and chemotherapy-related somatic symptom burden, increasing attention has been drawn to the health-related quality of life. The application of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) has been routinely recommended for the staging and response assessment of FDG-avid lymphoma. However, up till now, only a few researches have investigated the brain metabolic impairments in patients with pre-treatment lymphoma. The determination of the lymphoma-related metabolic brain pattern would facilitate exploring the tailored therapeutic regimen to alleviate not only the physiological, but also the psychological symptoms. In this retrospective study, we aimed to establish the diffuse large B-cell lymphoma-related pattern (DLBCLRP) of metabolic brain network and investigate the correlations between DLBCLRP and several indexes of the staging and response assessment.

RESULTS

The established DLBCLRP was characterized by the increased metabolic activity in bilateral cerebellum, brainstem, thalamus, striatum, hippocampus, amygdala, parahippocampal gyrus and right middle temporal gyrus and by the decreased metabolic activity in bilateral occipital lobe, parietal lobe, anterior cingulate gyrus, midcingulate cortex and medial frontal gyrus. Significant difference in the baseline expression of DLBCLRP was found among complete metabolic response (CMR), partial metabolic response (PMR) and progressive metabolic disease (PMD) groups (P < 0.01). DLBCLRP expressions were also significantly or tended to be positively correlated with international prognostic index (IPI) (rs = 0.306, P < 0.05), lg(total metabolic tumor volume, TMTV) (r = 0.298, P < 0.05) and lg(total lesion glycolysis, TLG) (r = 0.233, P = 0.064). Though no significant correlation of DLBCLRP expression was found with Ann Arbor staging or tumor SUVmax (P > 0.05), the post-treatment declines of DLBCLRP expression were significantly positively correlated with Ann Arbor staging (rs = 0.284, P < 0.05) and IPI (rs = 0.297, P < 0.05).

CONCLUSIONS

The proposed DLBCLRP would lay the foundation for further investigating the cerebral dysfunction related to DLBCL itself and/or treatments. Besides, the expression of DLBCLRP was associated with the tumor burden of lymphoma, implying a potential biomarker for prognosis.

Detecting microstructural alterations of cerebral white matter associated with breast cancer and chemotherapy revealed by generalized q-sampling MRI

Objective

Previous studies have discussed the impact of chemotherapy on the brain microstructure. There is no evidence of the impact regarding cancer-related psychiatric comorbidity on cancer survivors. We aimed to evaluate the impact of both chemotherapy and mental health problem on brain microstructural alterations and consequent cognitive dysfunction in breast cancer survivors.

Methods

In this cross-sectional study conducted in a tertiary center, data from 125 female breast cancer survivors who had not received chemotherapy (BB = 65; 49.86 ± 8.23 years) and had received chemotherapy (BA = 60; 49.82 ± 7.89 years) as well as from 71 age-matched healthy controls (47.18 ± 8.08 years) was collected. Chemotherapeutic agents used were docetaxel and epirubicin. We used neuropsychological testing and questionnaire to evaluate psychiatric comorbidity, cognitive dysfunction as well as generalized sampling imaging (GQI) and graph theoretical analysis (GTA) to detect microstructural alterations in the brain.

Findings

Cross-comparison between groups revealed that neurotoxicity caused by chemotherapy and cancer-related psychiatric comorbidity may affect the corpus callosum and middle frontal gyrus. In addition, GQI indices were correlated with the testing scores of cognitive function, quality of life, anxiety, and depression. Furthermore, weaker connections between brain regions and lower segregated ability were found in the post-treatment group.

Conclusion

This study suggests that chemotherapy and cancer-related mental health problem both play an important role in the development of white matter alterations and cognitive dysfunction.

Regional Brain Glucose Metabolism and Its Prognostic Value in Pretreatment Extranodal Natural Killer/T-Cell Lymphoma Patients

Objective

To explore regional brain glucose metabolic abnormalities of pretreatment stage I/II extranodal natural killer/T-cell lymphoma (ENKTL) patients using positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography (¹⁸F-FDG PET/CT) and assess its prognostic value.

Methods

Sixty pretreatment stage I/II ENKTL patients were enrolled in this retrospective study and divided into survival (n = 45) and death (n = 15) groups according to their status at the end of follow-up. A control group consisted of 60 healthy subjects. Regional cerebral glucose metabolism was evaluated on a voxel-by-voxel basis using statistical parametric mapping (SPM8) under a certain significance level (P < 0. 001) and voxel threshold (K = 100 voxels).

Results

Decreased metabolism was noted in patients, involving the bilateral prefrontal and orbitofrontal cortex, partial parietal and occipital cortex, cingulate gyrus and cerebellum; the sensorimotor cortex was largely spared. Increased metabolism was observed in the bilateral putamen, amygdala, and parahippocampal gyrus. Compared with the survival group, the death group had higher metabolism in the bilateral amygdala, putamen, left thalamus, uncus, and parahippocampal gyrus. Only B symptoms were associated with the increased metabolism of basal ganglia and thalamus (BGT). Patients with high metabolic tumor volume, total lesion glycolysis (TLG) and BGT metabolism had a poor prognosis. TLG and maximum standardized uptake value (SUVmax) LBGT/SUVmaxRight cerebellum were associated with Eastern Cooperative Oncology Group (ECOG) and prognostic index of natural killer lymphoma and Epstein-Barr virus-DNA (PINKE) scores. In multivariate analysis, only ECOG was an independent prognostic factor of both progression-free survival (PFS) and overall survival (OS). PINKE was an independent prognostic factor of OS.

Conclusion

Pretreatment stage I/II ENKTL patients exhibited abnormal regional cerebral glucose metabolism. Higher pretreatment glucose metabolism in BGT could predict a relatively poor prognosis but did not surpass the predictive values of ECOG and PINKE in stage I/II ENKTL patients.

Neurophysiologic and ophthalmic markers of chemotherapy-related cognitive impairment in patients diagnosed with hematologic cancer: A feasibility study

BACKGROUND

Biomarkers of chemotherapy-related cognitive impairment (CRCI) in hematologic cancer are understudied and underdeveloped. We evaluated the feasibility of using ophthalmic and neurophysiologic markers to assess CRCI in hematologic cancer.

METHODS

Hematologic cancer patients either receiving (Ctx+) or not receiving (Ctx-) chemotherapy were recruited from a tertiary medical center. Demographically-matched healthy controls (HC) were also recruited. Ctx+ participants completed the following study visits: (1) after diagnosis but prior to chemotherapy (baseline); (2) after one treatment cycle (one-month post-baseline); and (3) after three treatment cycles (three-months post-baseline). Comparison subjects completed assessments at similar intervals. Participants completed: (1) neuropsychological assessments of attention and executive function; (2) neurophysiologic assessments of control over spatial attention and working memory; and (3) ophthalmic assessments of contrast sensitivity and optical coherence tomography (OCT).

RESULTS

We enrolled 45 participants (15 per group), and 30 participants (Ctx+ = 8; Ctx- = 10; HC = 12) completed all study visits. Ctx+ participants performed worse than HC participants on neuropsychological measures of attention and executive function. Both Ctx+ and Ctx- participants showed changes in neurophysiologic measures of control over spatial attention that differed from HC participants. Ctx+ participants showed chemotherapy-related declines in contrast sensitivity that were predicted by OCT retinal nerve fiber layer thickness (RNFL) changes. Changes in neurophysiologic measures of control over spatial attention were also predicted by OCT RNFL changes.

CONCLUSION

We demonstrated the feasibility of using ophthalmic and neurophysiologic markers as rapid and non-invasive measures that may be useful for tracking CRCI in hematologic cancer.

Long-Term Clinical and Neuronuclear Imaging Sequelae of Cancer Therapy, Trauma, and Brain Injury

Neuronuclear imaging has been used for several decades in the study of primary neurodegenerative conditions, such as dementia and parkinsonian syndromes, both for research and for clinical purposes. There has been a relative paucity of applications of neuronuclear imaging to evaluate nonneurodegenerative conditions that can also have long-term effects on cognition and function. This article summarizes clinical and imaging aspects of 3 such conditions that have garnered considerable attention in recent years: cancer- and chemotherapy-related cognitive impairment, posttraumatic stress disorder, and traumatic brain injury. Further, we describe current research using neuroimaging tools aimed to better understand the relationships between the clinical presentations and brain structure and function in these conditions.

Neurophysiological evidence of impaired attention and working memory in untreated hematologic cancer patients

OBJECTIVE

Neuroimaging studies of hematologic cancer patients report altered activity in dorsal attention and central executive networks. To determine the consequences of these altered brain networks, we evaluated neurophysiological correlates of attention and working memory in hematologic cancer patients prior to initiating treatment.

METHODS

Hematologic cancer patients (19-80 years) were excluded for premorbid cognitive impairment, prior non-hematologic cancer diagnosis, and prior chemotherapy. Attention was manipulated by presenting an irrelevant spatial cue prior to visual search displays. Working memory was manipulated by presenting irrelevant distractors within memory displays. Electroencephalogram was recorded during task performance.

RESULTS

Patients (n = 28) and controls (n = 15) were balanced on age, gender, and education. Spatial cues evoked larger N2pc amplitudes, a correlate of spatial attention, in patients than controls (p < .05; Cohen's d > 0.7). Memory distractors evoked larger contralateral delay activity amplitudes, a correlate of working memory load, in patients (p = .028; Cohen's d = 1.1) but not controls (p = .64).

CONCLUSIONS

Prior to initiating treatment, hematologic cancer patients demonstrated poor control over spatial attention and working memory, consistent with altered dorsal attention and central executive network activity.

SIGNIFICANCE

Hematologic cancer patients may be at a higher risk for selecting, processing, and storing distracting information that would compete with more immediate goal-related behaviors.

Investigation of chemotherapy-induced brain structural alterations in breast cancer patients with generalized q-sampling MRI and graph theoretical analysis

BACKGROUND

Breast neoplasms are the most common cancer among women in Taiwan. Cognitive deficits are common complications of breast cancer survivors treated with chemotherapy. The most frequently observed disorders involve executive function and memory impairment. With improvements in tumor intervention and the consequent increase in the number of cancer survivors, the quality of life of patients has become an important issue. We are interested in the early effects of chemotherapy on the brain structures of patients. In addition, generalized q-sampling imaging (GQI), a wide range of q-space datasets for a more accurate and sophisticated diffusion MR approach, was first used in this topic.

METHODS

As diffusion tensor imaging (DTI) is associated with restrictions in the resolution of crossing fibers, we attempted to use GQI, which can overcome these difficulties and is advantageous over DTI for tractography of the crossing fibers. This cross-sectional study included two groups: breast cancer survivors who had completed their chemotherapy (n = 19) and healthy controls (n = 20). All participants underwent diffusion MRI exams and neuropsychological assessments. We included four parts in our image analysis, i.e., voxel-based statistical analysis, multiple regression analysis, graph theoretical analysis and network-based statistical analysis.

RESULTS

The results from the voxel-based statistical analysis showed significantly lower GFA and NQA values in the breast cancer group than those in the control group. We found significant positive correlations between the FACT-Cog and GQI indices. In the graph theoretical analysis, the breast cancer group demonstrated significantly longer characteristic path length. Adjuvant chemotherapy affected the integrity of white matter and resulted in poor cognitive performance, as indicated by the correlations between the neuropsychological assessment scales and the GQI indices. In addition, it was found that the characteristic path lengths in the breast cancer group increased, indicating that the brain network integration became worse.

CONCLUSIONS

Our study demonstrated alterations in structural brain networks and associated neuropsychological deficits among breast cancer survivors.

Identifying cytokine predictors of cognitive functioning in breast cancer survivors up to 10 years post chemotherapy using machine learning

INTRODUCTION

The purpose of this study is to explore 13 cytokine predictors of chemotherapy-related cognitive impairment (CRCI) in breast cancer survivors (BCS) 6 months to 10 years after chemotherapy completion using a multivariate, non-parametric approach.

METHODS

Cross sectional data collection included completion of a survey, cognitive testing, and non-fasting blood from 66 participants. Data were analyzed using random forest regression to identify the most significant predictors for each of the cognitive test scores.

RESULTS

A different cytokine profile predicted each cognitive test. Adjusted R² for each model ranged from 0.71-0.77 (p's < 9.50^-10). The relationships between all the cytokine predictors and cognitive test scores were non-linear.

CONCLUSIONS

Our findings are unique to the field of CRCI and suggest non-linear cytokine specificity to neural networks underlying cognitive functions assessed in this study.

Disrupted brain network functional dynamics and hyper-correlation of structural and functional connectome topology in patients with breast cancer prior to treatment

INTRODUCTION

Several previous studies have demonstrated that cancer chemotherapy is associated with brain injury and cognitive dysfunction. However, evidence suggests that cancer pathogenesis alone may play a role, even in non-CNS cancers.

METHODS

Using a multimodal neuroimaging approach, we measured structural and functional connectome topology as well as functional network dynamics in newly diagnosed patients with breast cancer. Our study involved a novel, pretreatment assessment that occurred prior to the initiation of any cancer therapies, including surgery with anesthesia. We enrolled 74 patients with breast cancer age 29-65 and 50 frequency-matched healthy female controls who underwent anatomic and resting-state functional MRI as well as cognitive testing.

RESULTS

Compared to controls, patients with breast cancer demonstrated significantly lower functional network dynamics (p = .046) and cognitive functioning (p < .02, corrected). The breast cancer group also showed subtle alterations in structural local clustering and functional local clustering (p < .05, uncorrected) as well as significantly increased correlation between structural global clustering and functional global clustering compared to controls (p = .03). This hyper-correlation between structural and functional topologies was significantly associated with cognitive dysfunction (p = .005).

CONCLUSIONS

Our findings could not be accounted for by psychological distress and suggest that non-CNS cancer may directly and/or indirectly affect the brain via mechanisms such as tumor-induced neurogenesis, inflammation, and/or vascular changes, for example. Our results also have broader implications concerning the importance of the balance between structural and functional connectome properties as a potential biomarker of general neurologic deficit.

Changes of Brain Glucose Metabolism in the Pretreatment Patients with Non-Small Cell Lung Cancer: A Retrospective PET/CT Study

OBJECTIVE

The tumor-to-brain communication has been emphasized by recent converging evidences. This study aimed to compare the difference of brain glucose metabolism between patients with non-small cell lung cancer (NSCLC) and control subjects.

METHODS

NSCLC patients prior to oncotherapy and control subjects without malignancy confirmed by 6 months follow-up were collected and underwent the resting state 18F-fluoro-D-glucose (FDG) PET/CT. Normalized FDG metabolism was calculated by a signal intensity ratio of each brain region to whole brain. Brain glucose metabolism was compared between NSCLC patients and control group using two samples t-test and multivariate test by statistical parametric maps (SPM) software.

RESULTS

Compared with the control subjects (n = 76), both brain glucose hyper- and hypometabolism regions with significant statistical differences (P<0.01) were found in the NSCLC patients (n = 83). The hypermetabolism regions (bilateral insula, putamen, pallidum, thalamus, hippocampus and amygdala, the right side of cerebellum, orbital part of right inferior frontal gyrus and vermis) were component parts of visceral to brain signal transduction pathways, and the hypometabolism regions (the left superior parietal lobule, bilateral inferior parietal lobule and left fusiform gyrus) lied in dorsal attention network and visuospatial function areas.

CONCLUSIONS

The changes of brain glucose metabolism exist in NSCLC patients prior to oncotherapy, which might be attributed to lung-cancer related visceral sympathetic activation and decrease of dorsal attention network function.

Impact of Cancer and Its Treatments on Cognitive Function: Advances in Research From the Paris International Cognition and Cancer Task Force Symposium and Update Since 2012

CONTEXT

Although cognitive impairments have been identified in patients with non-central nervous system cancer, especially breast cancer, the respective roles of cancer and therapies, and the mechanisms involved in cognitive dysfunction remain unclear.

OBJECTIVES

To report a state-of-the-art update from the International Cognitive and Cancer Task Force conference held in 2012.

METHODS

A report of the meeting and recent new perspectives are presented.

RESULTS

Recent clinical data support that non-central nervous system cancer per se may be involved in cognitive dysfunctions associated with inflammation parameters. The role of chemotherapy on cognitive decline was confirmed in colorectal and testicular cancers. Whereas the impact of hormone therapy remains debatable, some studies support a negative impact of targeted therapies on cognition. Regarding interventions, preliminary results of cognitive rehabilitation showed encouraging results. The methodology of future longitudinal studies has to be optimized by a priori end points, the use of validated test batteries, and the inclusion of control groups. Comorbidities and aging are important factors to be taken into account in future studies. Preclinical studies in animal models highlighted the role of cancer itself on cognition and support the possible benefits of prevention/care during chemotherapy. Progress in neuroimaging will help specify neural processes affected by treatments.

CONCLUSION

Clinical data and animal models confirmed that chemotherapy induces direct cognitive deficit. The benefits of cognitive rehabilitation are still to be confirmed. Studies evaluating the mechanisms underlying cognitive impairments using advanced neuroimaging techniques integrating the evaluation of genetic factors are ongoing.

Brain network alterations and vulnerability to simulated neurodegeneration in breast cancer

Breast cancer and its treatments are associated with mild cognitive impairment and brain changes that could indicate an altered or accelerated brain aging process. We applied diffusion tensor imaging and graph theory to measure white matter organization and connectivity in 34 breast cancer survivors compared with 36 matched healthy female controls. We also investigated how brain networks (connectomes) in each group responded to simulated neurodegeneration based on network attack analysis. Compared with controls, the breast cancer group demonstrated significantly lower fractional anisotropy, altered small-world connectome properties, lower brain network tolerance to systematic region (node), and connection (edge) attacks and significant cognitive impairment. Lower tolerance to network attack was associated with cognitive impairment in the breast cancer group. These findings provide further evidence of diffuse white matter pathology after breast cancer and extend the literature in this area with unique data demonstrating increased vulnerability of the post-breast cancer brain network to future neurodegenerative processes.

FDG-PET/CT assessment of differential chemotherapy effects upon skeletal muscle metabolism in patients with melanoma

OBJECTIVES

To quantify the differential effects of chemotherapy on the metabolic activity of skeletal muscle in vivo using molecular imaging with [18F]-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT).

METHODS

In this retrospective study, 21 subjects with stage IV melanoma who underwent pre- and post-chemotherapy whole-body FDG-PET/CT imaging were included. The mean standardized uptake value (SUVmean) of 8 different skeletal muscles was measured per subject. Pre- and post-treatment measurements were then averaged across all subjects for each muscle and compared for statistically significant differences between the muscles and following different chemotherapy regimens including dacarbazine (DTIC) and temozolomide (TMZ).

RESULTS

Analysis of FDG-PET/CT images reliably detected changes in skeletal muscle metabolic activity based on muscle location. The percent change in metabolic activity of each skeletal muscle in each subject following chemotherapy was observed to be related to the type of chemotherapy received. Subjects receiving DTIC generally had a decrease in metabolic activity of all muscle groups, whereas subjects receiving TMZ generally had an increase in muscle activity of all muscle groups.

CONCLUSION

FDG-PET/CT can reveal baseline metabolic differences between different muscles of the body. Different chemotherapies are associated with differential changes in the metabolic activity of skeletal muscle, which can be detected and quantified with FDG-PET/CT.