Tumor-related neurocognitive dysfunction in patients with diffuse glioma: a systematic review of neurocognitive functioning prior to anti-tumor treatment

Tumor-related neurocognitive dysfunction in patients with diffuse glioma: a retrospective cohort study prior to antitumor treatment

BACKGROUND

Impairments in neurocognitive functioning (NCF) frequently occur in glioma patients. Both the tumor and its treatment contribute to these impairments. We aimed to quantify NCF in glioma patients before treatment and to investigate which factors influence NCF.

METHODS

We performed a retrospective cohort study in diffuse glioma patients according to STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) criteria. All patients had undergone neuropsychological assessment as part of routine clinical care, before awake surgery. We studied "overall NCF" and NCF in 5 neurocognitive domains separately. For "overall NCF" and per domain, we performed analyses at 2 different levels of outcome measures: (1) group level: mean cognitive functioning of the study sample, and (2) individual level: the percentage of impaired patients. We performed multivariable logistic regression analyses to investigate which factors were associated with the occurrence of cognitive impairments.

RESULTS

From our cohort of glioma patients (2010-2016), 168 patients met all the inclusion criteria. All cognitive domains were significantly affected at the group level. The percentages of neurocognitive impairments (-2SD) were highest for Executive Functioning, Psychomotor Speed, and Memory (26.5%, 23.2%, and 19.3%, respectively). Patients with high-grade glioma were affected more severely than patients with low-grade glioma. Tumor volume, isocitrate dehydrogenase status, WHO grade, and histology were associated with the occurrence of domain-specific impairments.

CONCLUSIONS

Cognitive impairment occurs in the majority of treatment-naive glioma patients. The domains Executive Functioning, Speed, and Memory are involved most frequently. These impairments in NCF are explained not only by tumor location and volume, but also by other (biological) mechanisms.

Resting-state functional connectivity predicts individual language impairment of patients with left hemispheric gliomas involving language network

Language deficits following brain tumors should consider the dynamic interactions between different tumor growth kinetics and functional network reorganization. We measured the resting-state functional connectivity of 126 patients with left cerebral gliomas involving language network areas, including 77 patients with low-grade gliomas (LGG) and 49 patients with high-grade gliomas (HGG). Functional network mapping for language was performed by construction of a multivariate machine learning-based prediction model of individual aphasia quotient (AQ), a summary score that indicates overall severity of language impairment. We found that the AQ scores for HGG patients were significantly lower than those of LGG patients. The prediction accuracy of HGG patients (R² = 0.27, permutation P = 0.007) was much higher than that of LGG patients (R² = 0.09, permutation P = 0.032). The rsFC regions predictive of LGG's AQ involved the bilateral frontal, temporal, and parietal lobes, subcortical regions, and bilateral cerebro-cerebellar connections, mainly in regions belonging to the canonical language network. The functional network of language processing for HGG patients showed strong dependence on connections of the left cerebro-cerebellar connections, limbic system, and the temporal, occipital, and prefrontal lobes. Together, our findings suggested that individual language processing of glioma patients links large-scale, bilateral, cortico-subcortical, and cerebro-cerebellar functional networks with different network reorganizational mechanisms underlying the different levels of language impairments in LGG and HGG patients.

Cognitive functioning in glioma patients is related to functional connectivity measures of the non-tumoural hemisphere

Previous studies have shown that cognitive functioning in patients with brain tumour is associated with the functional network characteristics of specific resting‐state networks or with whole‐brain network characteristics. These studies, however, did not acknowledge the functional contribution of areas in the contralesional, non‐tumoural hemisphere, even though these healthy remote areas likely play a critical role in compensating for the loss of function in damaged tissue. In the current study, we examined whether there is an association between cognitive performance and functional network features of the contralesional hemisphere of patients with glioma. We found that local efficiency of the contralesional hemisphere was associated with performance on the reaction time domain, whereas contralesional assortativity was associated with complex attention and cognitive flexibility scores. Our results suggest that a less segregated organization of the contralesional hemisphere is associated with better reaction time scores, whereas a better spread of information over the contralesional hemisphere through mutually interconnected contralesional hubs is associated with better cognitive flexibility and better complex attention scores. These findings urge researchers to recognize the functional contribution of remote, undamaged regions and to focus more on the graph metrics of the contralesional hemisphere in the search for predictors of cognitive functioning in patients with brain tumour.

Cognitive functioning following brain irradiation as part of cancer treatment: Characterizing better cognitive performance

OBJECTIVE

Although brain radiation therapy (RT) impacts cognitive function, little is known about the subset of survivors with minimal cognitive deficits. This study compares the characteristics of patients receiving brain irradiation as part of cancer treatment with minimal cognitive deficits to those with poorer cognitive functioning.

METHODS

Adults at least 6 months postbrain RT (N = 198) completed cognitive measures of attention, memory, and executive functions. Cognitive functioning was categorized into better- and poorer-performing groups, with better-performing survivors scoring no worse than 1.5 standard deviations below the published normative mean on all cognitive measures. Logistic regression was used to identify variables associated with better-performing group membership.

RESULTS

Approximately 25% of the sample met the criteria for the better-performing group. In unadjusted analyses, RT type (whole brain irradiation and partial brain irradiation), sedating medications, and fatigue were independently associated with cognition. Sociodemographic and other clinical characteristics were not significant. In adjusted analyses, only fatigue remained significantly associated with group membership (OR = 1.05, 95% CI = 1.01-1.09, P = .009).

CONCLUSIONS

There is a subgroup of survivors with minimal long-term cognitive deficits despite undergoing a full course of brain RT as part of cancer treatment. Lower fatigue had the strongest association with better cognitive performance. Interventions targeting cancer-related fatigue may help buffer the neurotoxic effects of brain RT.

Neurocognitive evaluation in older adult patients affected by glioma

BACKGROUND

Glioblastoma (GBM) has an increasing incidence and dismal prognosis in older adults. This study evaluated neurocognitive status of an older adult population with GBM and its correlation with clinical and demographical variables.

METHODS

Each patient underwent an extended neuropsychological evaluation by means of a battery of standardized tests describing eight cognitive domains: global function; verbal learning; short- and long-term memory (LTM); executive functions (EFs); abstract reasoning (AR); attention; and visuo-constructional abilities (CA).

RESULTS

We assessed 79 patients with GBM (median age: 74 years). Out of this initial sample, a subgroup of seventeen patients with six-month median time underwent a follow-up test session. 46 out of the 79 patients (58.2%) presented multi-domain cognitive impairment, 24 patients (30.3%) showed single-domain cognitive impairment and only seven (9%) showed no cognitive impairment. Kaplan Meier estimator showed that patients with AR deficit had a poorer prognosis in terms of progression-free survival and overall survival (p < .001). At the multivariate analysis AR (deficit vs non; hazard ratio (HR) = 5.07, 95%; confidence interval (CI): 1.91-13.46; p < .001) was correlated with disease progression and overall survival, AR (deficit vs non; HR = 7.24, 95% CI: 2.58-20.32; p < .001). Eight out of seventeen patients who underwent follow-up test session showed cognitive improvement, five resulted in further deterioration, and four patients remained stable. LTM, EF, and CA were the most affected functions at follow-up, while verbal learning was the most improved one in patients with cognitive improvement.

CONCLUSIONS

Cognitive functioning evaluation should be included among the standard clinical endpoints in the treatment of older adult neuro-oncology patients.

Diffusion Tensor Imaging Reveals Microstructural Heterogeneity of Normal-Appearing White Matter and Related Cognitive Dysfunction in Glioma Patients

Immunohistochemical data based on isocitrate–dehydrogenase (IDH) mutation status have redefined glioma as a whole-brain disease, while occult tumor cell invasion along white matter fibers is inapparent in conventional magnetic resonance imaging (MRI). The functional and prognostic impact of focal glioma may however relate to the extent of white matter involvement. We used diffusion tensor imaging (DTI) to investigate microstructural characteristics of whole-brain normal-appearing white matter (NAWM) in relation to cognitive functions as potential surrogates for occult white matter involvement in glioma. Twenty patients (12 IDH-mutated) and 20 individually matched controls were preoperatively examined using DTI combined with a standardized neuropsychological examination. Tumor lesions including perifocal edema were masked, and fractional anisotropy (FA) as well as mean, radial, and axial diffusivity (MD, RD, and AD, respectively) of the remaining whole-brain NAWM were determined by using Tract-Based Spatial Statistics and histogram analyses. The relationship between extratumoral white matter integrity and cognitive performance was examined using partial correlation analyses controlling for age, education, and lesion volumes. In patients, mean FA and AD were decreased as compared to controls, which agrees with the notion of microstructural impairment of NAWM in glioma patients. Patients performed worse in all cognitive domains tested, and higher anisotropy and lower MD and RD values of NAWM were associated with better cognitive performance. In additional analyses, IDH-mutated and IDH-wildtype patients were compared. Patients with IDH-mutation showed higher FA, but lower MD, AD, and RD values as compared to IDH-wildtype patients, suggesting a better preserved microstructural integrity of NAWM, which may relate to a less infiltrative nature of IDH-mutated gliomas. Diffusion-based phenotyping and monitoring microstructural integrity of extratumoral whole-brain NAWM may aid in estimating occult white matter involvement and should be considered as a complementary biomarker in glioma.

Risk factors for neurocognitive impairment in patients with benign intracranial lesions

This study was designed to assess risk factors for neurocognitive impairment in patients with benign intracranial lesions including tumors and vascular lesions. 74 patients (29 m, 51 f, mean age 54.4 years) with surgery for benign intracranial lesions were included in this prospective single-center study. Extensive neuropsychological testing was performed preoperatively, including tests for attention, memory and executive functions. Furthermore, headache and depression were assessed using the german version of the HDI (IBK) and the BDI-II. Multiple linear regression analyses of the percentile ranks (adjusted for age, sex and education) including the parameters age, Karnofsky Performance Status Scale (KPS), mood, pain and lesion size were performed to identify risk factors for cognitive impairment. Using the Mann-Whitney U test, the influence of hemisphere and type of lesion (tumor/vascular) was assessed. Posthoc Bonferroni correction was performed. Poorer neurocognitive functions were observed only in the category attention in patients with higher age (divided attention, WMS) and reduced KPS (WMS). Lesion volume, mood, pain, hemisphere or the type of the lesion (tumor, vascular) were not identified as risk factors for poorer neurocognitive functions in patients with benign intracranial lesions. Age and KPS are the main risk factors for poorer neurocognitive functions in the category attention in patients with benign intracranial lesions. Knowledge of these risk factors might be important to find appropriate therapy regimes to improve cognitive functions and quality of life.

Management for Different Glioma Subtypes: Are All Low-Grade Gliomas Created Equal?

Following the identification of key molecular alterations that provided superior prognostication and led to the updated 2016 World Health Organization (WHO) Central Nervous System (CNS) Tumor Classification, the understanding of glioma behavior has rapidly evolved. Mutations in isocitrate dehydrogenase (IDH) 1 and 2 are present in the majority of adult grade 2 and 3 gliomas, and when used in conjunction with 1p/19q codeletion for classification, the prognostic distinction between grade 2 versus grade 3 is diminished. As such, the previously often used term of "low-grade glioma," which referred to grade 2 gliomas, has now been replaced by the phrase "lower-grade glioma" to encompass both grade 2 and 3 tumors. Additional molecular characterization is ongoing to even further classify this heterogeneous group of tumors. With such a colossal shift in the understanding of lower-grade gliomas, management of disease is being redefined in the setting of emerging molecular-genetic biomarkers. In this article, we review recent progress and future directions regarding the surgical, radiotherapeutic, chemotherapeutic, and long-term management of adult lower-grade gliomas.

Long-term cognitive dysfunction after radiation therapy for primary brain tumors

Background: The extent of radiation therapy (RT)-induced changes in cognitive function is unknown. RT with protons instead of photons spares the healthy brain tissue more and is believed to reduce the risk of cognitive dysfunction. There is modest knowledge on which parts of the brain we need to spare, to prevent cognitive dysfunction. To uncover which cognitive domains is most affected, we compared cognitive functioning in brain tumor patients treated with neurosurgery and RT with brain tumor patients treated with neurosurgery alone. Methods: A cross-sectional study assessing cognitive function in 110 patients with a primary brain tumor grades I-III or medulloblastoma (grade IV) treated at Aarhus University Hospital (AUH), Denmark between 2006 and 2016. Two cohorts were established: a cohort of 81 brain tumor patients who had received neurosurgery followed by RT (RT+), and a cohort of 29 brain tumor patients who had only received neurosurgery (RT-). The patients underwent questionnaires and neuropsychological assessment with standardized tests. Results: Mean age was 53.5 years with an average time since diagnosis of 7.3 years. Compared with normative data, lower average scores were observed for the entire group on domains concerning of verbal learning and memory (p < .001), attention and working memory (p < .001), processing speed (p < .001), and executive functioning (p < .001). Compared to RT- patients, RT + patients scored lower on domains concerning processing speed (p = .04) and executive function (p = .05) and had higher impairment frequency on verbal fluency (p = .02) with 16% of patients exceeding 1.5 SD below normative data. Conclusions: Our results indicate that treatment, including RT, for a primary brain tumor may have negative long-term impact on cognitive function, especially on processing speed and executive function.

A systematic review of cognitive function in patients with glioblastoma undergoing surgery

Background

Patients with glioblastoma (GB) are more likely to suffer cognitive deficits with poor quality of life as compared with lower-grade glioma patient groups, for whom cognition research is plentiful. The objective of this systematic review is to evaluate the cognitive function of patients with GB before and after surgery.

Methods

This review was prospectively registered with PROSPERO. PubMed and EMBASE searches were performed, most recently March 15, 2018. Inclusion criteria were adult patients, histologically confirmed GB, and cognitive tests conducted before and/or after surgery. Screening and data extraction were carried out independently by 2 authors.

Results

A total of 512 abstracts were screened. Nineteen studies were included with 902 participants, of whom only 423 had histologically confirmed GB. Only 11 studies tested cognitive function both before and after surgery. A total of 114 different cognitive tests were used. The most common test was used in only 9 studies; 82 tests were used only once. Follow-up time ranged from 1 week to 16 months with extremely high dropout rates. Eighteen of 19 studies reported cognitive deficits in their samples, with prevalence ranging from 22% to 100% (median 64%, interquartile range 42%). Only 1/11 longitudinal studies reported normal cognitive function, 3/11 reported initial deficits with improvement after surgery, 3/11 reported static deficits, and 4/11 reported deterioration.

Conclusion

There is a consistently high risk of cognitive deficit for patients with GB undergoing surgery. The included studies showed marked heterogeneity in study design, case-mix of included diagnoses, and the type and timing of cognitive tests used. We highlight considerations for the design of future studies to avoid such bias.

Evaluation of the content coverage of questionnaires containing basic and instrumental activities of daily living (ADL) used in adult patients with brain tumors

Background

Everyday functioning can be assessed using measures of basic activities of daily living (BADL) or instrumental activities of daily living (IADL). The aim of this review was to provide an overview of the scope and specific content of BADL and/or IADL covered by currently used questionnaires in adult brain tumor patient studies.

Methods

Electronic databases were searched up to April 2017 to identify all eligible questionnaires with items regarding BADL/IADL in studies with adult brain tumor patients. Articles were selected using predetermined in- and exclusion criteria. Items with similar content were clustered into domains based on type of activity.

Results

Thirty-one unique questionnaires containing at least one BADL and/or IADL item were identified; 21 and 29 questionnaires containing ≥ 1 BADL or IADL item, respectively. The percentage of ADL items in these questionnaires ranged from 4 to 100%. Only two questionnaires were specifically developed to measure BADL (Barthel Index and Katz-ADL) and two specifically for IADL (Lawton-Brody IADL and preliminary IADL-BN). Content clustering revealed that IADL had a larger variation in content (31 domains, e.g. work or leisure time activities) compared to BADL (15 domains, e.g. mobility or bathing/washing).

Conclusion

Thirty-one questionnaires previously used in brain tumor studies contained items on BADL and/or IADL and covered a wide range of content, in particular for IADL. It is currently unclear which BADL/IADL are most relevant for brain tumor patients, and this should therefore be evaluated. Next, existing questionnaires could be adapted or validated, or new measures can be developed to meet these needs.

Electronic supplementary material

The online version of this article (10.1007/s11060-019-03136-9) contains supplementary material, which is available to authorized users.

The Impacts of Tumor and Tumor Associated Epilepsy on Subcortical Brain Structures and Long Distance Connectivity in Patients With Low Grade Glioma

Low grade gliomas in cerebral cortex often cause symptoms related to higher cerebral functions such as attention, memory and executive function before treatment is initiated. Interestingly, focal tumors residing in one cortical region can lead to a diverse range of symptoms, indicating that the impact of a tumor is extended to multiple brain regions. We hypothesize that the presence of focal glioma in the cerebral cortex leads to alterations of distant subcortical areas and essential white matter tracts. In this study, we analyzed diffusion tensor imaging scans in glioma patients to study the effect of glioma on subcortical gray matter nuclei and long-distance connectivity. We found that the caudate nucleus, putamen and thalamus were affected by cortical glioma, displaying both volumetric and diffusion alterations. The cerebellar cortex contralateral to the tumor side also showed significant volume decrease. Additionally, tractography of the cortico-striatal and cortico-thalamic projections shows similar diffusion alterations. Tumor associated epilepsy might be an important contributing factor to the found alterations. Our findings indeed confirm concurrent structural and connectivity abrasions of brain areas distant from brain tumor, and provide insights into the pathogenesis of diverse neurological symptoms in glioma patients.

Rescue of cognitive function following fractionated brain irradiation in a novel preclinical glioma model

More than half of long-term brain tumor survivors develop irreversible cognitive decline that severely affect their quality of life. However, there is no pre-clinical model that allows long-term assessment of cognition, and there is no treatment which ameliorates cognitive deficits in patients. Here, we report a novel glioma mouse model that offers manageable tumor growth and reliable assessment of cognitive functions in a post-treatment manner. Using this model, we found that fractionated whole-brain irradiation (fWBI), but not tumor growth, results in memory deficits. Transient inhibition of CSF-1R during fWBI prolongs survival of glioma-bearing mice and fully prevents fWBI-induced memory deficits. This result suggests that CSF-1R inhibition during radiotherapy can be explored as an approach to improve both survival and cognitive outcomes in patients who will receive fWBI. Taken together, the current study provides a proof of concept of a powerful tool to study radiation-induced cognitive deficits in glioma-bearing animals.

Incidence trends, rates, and ethnic variations of primary CNS tumors in Texas from 1995 to 2013

Background

Although rare, primary central nervous system (CNS) tumors are associated with significant morbidity and mortality. Texas is a representative sample of the United States population given its large population, ethnic disparities, geographic variations, and socio-economic differences. This study used Texas data to determine if variations in incidence trends and rates exist among different ethnicities in Texas.

Methods

Data from the Texas Cancer Registry from 1995 to 2013 were examined. Joinpoint Regression Program software was used to obtain the incidence trends and SEER*Stat software was used to produce average annual age-adjusted incidence rates for both nonmalignant and malignant tumors in Texas from 2009 to 2013.

Results

The incidence trend of malignant primary CNS tumors in whites was stable from 1995 to 2002, after which the annual percent change decreased by 0.99% through 2013 (95% CI, -1.4, -0.5; P = .04). Blacks and Asian/Pacific Islanders showed unchanged incidence trends from 1995 to 2013. Hispanics had an annual percent change of -0.83 (95% CI, -1.4, -0.2; P = .009) per year from 1995 through 2013. From 2009 to 2013, the incidence rates of nonmalignant and malignant primary CNS tumors were highest among blacks, followed by whites, Hispanics, Asians, and American Indians/Alaskan Natives.

Conclusions

Consistent with the 2016 Central Brain Tumor Registry of the United States report, the black population in Texas showed the highest total incidence of CNS tumors of any other race studied. Many factors have been proposed to account for the observed differences in incidence rate including geography, socioeconomic factors, and poverty factors, although the evidence for these external factors is lacking.

Group Changes in Cognitive Performance After Surgery Mask Changes in Individual Patients with Glioblastoma

BACKGROUND

There is a growing interest to include evaluations of cognitive performance in the clinical management of patients with glioblastoma (GBM). However, as changes in cognitive performance of a group may mask changes in individual patients, study results are often difficult to transfer into clinical practice. We focused on the comparison of group versus individual changes in neuropsychological performance of patients with GBM after initial surgical treatment.

METHODS

Patients underwent neuropsychological evaluation using CNS Vital Signs 1 day prior to and 3 months after surgery. Two-tailed paired-samples t tests were conducted to assess changes on the group level. Reliable change indices (RCIs) that correct for practice effects and imperfect test-retest reliabilities were used to examine changes in individual patients.

RESULTS

Cognitive dysfunction was common (>80%) both before and 3 months after surgery in this sample of 82 patients with GBM. Whereas group analyses revealed minimal changes in performance over time, RCIs demonstrated that most patients (89%) showed changes in performance in at least 1 cognitive domain. Half of these individual patients solely showed improvements, a quarter solely showed declines, and another quarter showed both improvements and declines.

CONCLUSIONS

This study clearly demonstrates that important individual changes in performance are masked when looking only at group results. Future studies should more often use an individual patient approach to enhance knowledge transfer into clinical practice.

Pretreatment Cognition in Patients Diagnosed With Pediatric Brain Tumors

BACKGROUND

There is a large body of literature identifying risk factors for the long-term cognitive alterations found in survivors of pediatric brain tumors. Less is known about baseline cognitive functioning in this population, but studies suggest that cognitive dysfunctions are often present at the time of diagnosis. This study aimed to identify potential risk factors for lower cognitive function at the time of pediatric brain tumor diagnosis.

METHODS

Participants were children and adolescents (n = 101) diagnosed with a pediatric brain tumor between 2006 and 2015, who underwent a pretreatment neuropsychologic assessment. Multivariate regression models were used to estimate the association between gender, age at diagnosis, tumor size and location, increased intracranial pressure, epilepsy, and six different indicators of cognitive functioning.

RESULTS

Overall, cognitive performance was relatively intact, with results close to norm means, but impairments were found in memory and cognitive processing speed. Male gender, older age, epilepsy, increased intracranial pressure, and larger tumors were all associated with lower cognitive function at the time of brain tumor diagnosis; whereas tumor location was not.

CONCLUSIONS

Pretreatment neuropsychologic assessments, with some adjustments, can be carried out with children and adolescents with brain tumors. Our study adds to a small but growing body of literature documenting cognitive impairments at the time of diagnosis; these impairments may partly explain the longer-term deficits that commonly occur in pediatric brain tumor survivors. Consistent with previous research, pretreatment impairments were more common among boys, older children, and those with increased intracranial pressure, epilepsy, and larger tumors. The relationship between baseline and longer-term cognitive deficits requires further examination.

An attempt to conceptualize the individual onco-functional balance: Why a standardized treatment is an illusion for diffuse low-grade glioma patients

In the era of evidence-based medicine, clinicians aim to establish standards of care from randomized studies. Following, personalized medicine has emerged, as new individualized biomarkers could help to predict sensitivity to specific treatment. In this paper, we show that, for diffuse low-grade glioma, some specificities - dual goal of both survival and functional gain, long duration of the disease with multistep treatments, multiparametric evaluation of the onco-functional balance of each treatment modality - call for a change of paradigm. After summarizing how to weight the benefits and risks of surgery, chemotherapy and radiotherapy, we show that the overall efficacy of a treatment modality cannot be assessed per se, as it depends on its integration in the whole sequence. Then, we revisit the notion of personalized medicine: instead of decision-making based solely on molecular profile, we plead for a recursive algorithm, allowing a dynamic evaluation of the onco-functional balance, integrating many individual characteristics of the patient's tumor and brain function.