Is basic research providing answers if adjuvant anti-estrogen treatment of breast cancer can induce cognitive impairment?

Association of Cancer History with Lifetime Risk of Dementia and Alzheimer's Disease

Background

The literature presents conflicting results regarding the potential protective effect of prevalent cancer on the development of dementia and Alzheimer's disease (AD).

Objective

Association between cancer and subsequent risk of dementia and/or AD was reported previously, but survival bias has been of concern. Here, we aimed to calculate the lifetime risk of dementia and AD and evaluate the association of cancer history with these two conditions.

Methods

In this retrospective analysis, we included 292,654 participants aged 60+ y during the follow-up and free of dementia at baseline, within the UK Biobank cohort. Lifetime risks of dementia and AD were estimated in individuals with and without cancer history, and different durations of cancer exposure and cancer types.

Results

During a median of 12.5 follow-up years, 5,044 new dementia and 2,141 AD cases were reported. Lifetime risks of dementia and AD were lower in cancer survivors compared to those without cancer, and this effect was more pronounced in participants with cancer history exposure≥5 years. Similar relationship was observed in individual cancer types, except for breast cancer.

Conclusions

Results suggested an inverse association between cancer history and lifetime risk of dementia and AD, which may be modified by different cancer types and cancer exposure time.

Adjuvant aromatase inhibitor treatment worsens depressive symptoms and sleep quality in postmenopausal women with localized breast cancer: A one-year follow-up study

First-line treatment in postmenopausal women with estrogen- and/or progesterone-positive breast cancer consists of aromatase inhibitors (AROi). The ability of AROi to promote or worsen cognitive function, depressive symptoms, sleep quality and performance in basic activities of daily life as primary and concomitant outcomes in long longitudinal studies in post-menopausal women has been seldom investigated. This study is a cohort trial which aimed to determine if there were differences in cognitive function assessment, depressive symptoms, and sleep quality after 1 year under AROi treatment and to determine the interrelations between these symptoms.

METHODS

A prospective 1-year longitudinal study was performed in a representative sample of tertiary hospital. Women with localized breast cancer newly treated with AROi therapy were evaluated for cognitive functions, depressive symptoms, sleep problems and ability to perform basic activities of the daily life at baseline and after 6 months and 12 months under adjuvant AROi treatment.

RESULTS

Analysis of cognitive functions by the Mini-Mental State Examination (MMSE) scores did not show significantly worsening under AROi treatment after 6 months and 12 months of treatment compared to the baseline. Analysis of depressive symptoms with the Geriatric Depression Scale and sleep quality with the Athens Insomnia Scale (AIS) scores showed significant (p < 0.05) changes after 6 and 12 months of treatment with AROi, with women describing more depressive symptoms and more sleep disturbances.

CONCLUSIONS

Our study found impairments in sleep quality and an increase in depressive symptoms, which has important implications for clinicians as they impair quality of life and adherence to treatment.

Chemobrain in Breast Cancer: Mechanisms, Clinical Manifestations, and Potential Interventions

Among the potential adverse effects of breast cancer treatment, chemotherapy-related cognitive impairment (CRCI) has gained increased attention in the past years. In this review, we provide an overview of the literature regarding CRCI in breast cancer, focusing on three main aspects. The first aspect relates to the molecular mechanisms linking individual drugs commonly used to treat breast cancer and CRCI, which include oxidative stress and inflammation, reduced neurogenesis, reduced levels of specific neurotransmitters, alterations in neuronal dendrites and spines, and impairment in myelin production. The second aspect is related to the clinical characteristics of CRCI in patients with breast cancer treated with different drug combinations. Data suggest the incidence rates of CRCI in breast cancer vary considerably, and may affect more than 50% of treated patients. Both chemotherapy regimens with or without anthracyclines have been associated with CRCI manifestations. While cross-sectional studies suggest the presence of symptoms up to 20 years after treatment, longitudinal studies confirm cognitive impairments lasting for at most 4 years after the end of chemotherapy. The third and final aspect is related to possible therapeutic interventions. Although there is still no standard of care to treat CRCI, several pharmacological and non-pharmacological approaches have shown interesting results. In summary, even if cognitive impairments derived from chemotherapy resolve with time, awareness of CRCI is crucial to provide patients with a better understanding of the syndrome and to offer them the best care directed at improving quality of life.

Effects of Endocrine Therapy on Cognitive Function in Patients with Breast Cancer: A Comprehensive Review

Simple Summary

Many persons diagnosed with breast cancer are treated with endocrine therapy and will experience the side effects of endocrine therapy. Cognitive adverse effects of endocrine therapy are increasingly being recognised, and can significantly affect quality of life, adherence and treatment outcome. This review aims to discuss the nature of cognitive dysfunction associated with endocrine therapy, the mechanisms underpinning its development, and evidence-based management strategies.

Abstract

Endocrine therapy forms the backbone of systemic therapy for the majority of persons with early and late-stage breast cancer. However, the side effects can negatively affect quality of life, and impact treatment adherence and overall oncological outcomes. Adverse effects on cognition are common, underreported and challenging to manage. We aim to describe the nature, incidence, risk factors and underlying mechanisms of endocrine therapy-induced cognitive dysfunction. We conducted a comprehensive literature review of the studies reporting on cognitive dysfunction associated with endocrine therapies for breast cancer. We also summarise prevention and treatment strategies, and ongoing research. Given that patients are taking endocrine therapies for longer durations than ever before, it is essential that these side effects are managed pro-actively within a multi-disciplinary team in order to promote adherence to endocrine therapy and improve patients’ quality of life.

Prevalence of cognitive impairment following chemotherapy treatment for breast cancer: a systematic review and meta-analysis

Breast cancer survival rates have markedly improved. Consequently, survivorship issues have received increased attention. One common sequel of treatment is chemotherapy-induced cognitive impairment (CICI). CICI causes a range of impairments that can have a significant negative impact on quality of life. Knowledge of the prevalence of this condition is required to inform survivorship plans, and ensure adequate resource allocation and support is available for sufferers, hence a systematic review of prevalence data was performed. Medline, Scopus, CINAHL and PSYCHInfo were searched for eligible studies which included prevalence data on CICI, as ascertained though the use of self-report, or neuropsychological tests. Methodological quality of included studies was assessed. Findings were synthesised narratively, with meta-analyses being used to calculate pooled prevalence when impairment was assessed by neuropsychological tests. The review included 52 studies. Time-points considered ranged from the chemotherapy treatment period to greater than 10 years after treatment cessation. Summary prevalence figures (across time-points) using self-report, short cognitive screening tools and neuropsychological test batteries were 44%, 16% and 21–34% respectively (very low GRADE evidence). Synthesised findings demonstrate that 1 in 3 breast cancer survivors may have clinically significant cognitive impairment. Prevalence is higher when self-report based on patient experience is considered. This review highlights a number of study design issues that may have contributed to the low certainty rating of the evidence. Future studies should take a more consistent approach to the criteria used to assess impairment. Larger studies are urgently needed.

Effect of physical exercise on cognitive function and brain measures after chemotherapy in patients with breast cancer (PAM study): protocol of a randomised controlled trial

INTRODUCTION

After treatment with chemotherapy, many patients with breast cancer experience cognitive problems. While limited interventions are available to improve cognitive functioning, physical exercise showed positive effects in healthy older adults and people with mild cognitive impairment. The Physical Activity and Memory study aims to investigate the effect of physical exercise on cognitive functioning and brain measures in chemotherapy-exposed patients with breast cancer with cognitive problems.

METHODS AND ANALYTICS

One hundred and eighty patients with breast cancer with cognitive problems 2-4 years after diagnosis are randomised (1:1) into an exercise intervention or a control group. The 6-month exercise intervention consists of twice a week 1-hour aerobic and strength exercises supervised by a physiotherapist and twice a week 1-hour Nordic or power walking. The control group is asked to maintain their habitual activity pattern during 6 months. The primary outcome (verbal learning) is measured at baseline and 6 months. Further measurements include online neuropsychological tests, self-reported cognitive complaints, a 3-tesla brain MRI, patient-reported outcomes (quality of life, fatigue, depression, anxiety, work performance), blood sampling and physical fitness. The MRI scans and blood sampling will be used to gain insight into underlying mechanisms. At 18 months online neuropsychological tests, self-reported cognitive complaints and patient-reported outcomes will be repeated.

ETHICS AND DISSEMINATION

Study results may impact usual care if physical exercise improves cognitive functioning for breast cancer survivors.

TRIAL REGISTRATION NUMBER

NTR6104.

How to Identify and Manage Cognitive Dysfunction After Breast Cancer Treatment

Attention and memory dysfunction is a common complaint among patients with breast cancer that can be reported during and up to several years after treatment. It can negatively affect patients' quality of life and their ability to work. This phenomenon has mainly been studied in patients with breast cancer who are treated with adjuvant chemotherapy. Women describe concentration problems and difficulties with word finding, multitasking, or remembering new information, as well as more effort and time needed to accomplish these tasks. Such cognitive dysfunction is subtle or moderate and occurs in 15% to 25% of patients. Older patients seem more likely to experience cognitive decline with chemotherapy than do young women with breast cancer. Patients who report that cognitive dysfunction has affected their daily lives for 6 to 12 months after the end of chemotherapy or during hormone therapy may need referral to a neuropsychologist. During the cognitive assessment, the etiology of their cognitive complaints is sought and neuropsychological tests are administered to assess objective cognitive functioning. Psychological factors-fatigue and pain-should be assessed systematically with cognitive complaints to identify precisely the cause of the problems. A nonpharmacologic approach-mainly cognitive rehabilitation-seems to be the most promising for the management of these difficulties, but these preliminary results require confirmation. In the future, early detection of cognitive impairment and cognitive rehabilitation should be included in the portfolio of oncology supportive care to facilitate the return to work of young women and to avoid potential repercussions on adherence to oral treatments and on autonomy in older patients.

Assay of Calcium Transients and Synapses in Rat Hippocampal Neurons by Kinetic Image Cytometry and High-Content Analysis: An In Vitro Model System for Postchemotherapy Cognitive Impairment

Postchemotherapy cognitive impairment (PCCI) is commonly exhibited by cancer patients treated with a variety of chemotherapeutic agents, including the endocrine disruptor tamoxifen (TAM). The etiology of PCCI is poorly understood. Our goal was to develop high-throughput assay methods to test the effects of chemicals on neuronal function applicable to PCCI. Rat hippocampal neurons (RHNs) were plated in 96- or 384-well dishes and exposed to test compounds (forskolin [FSK], 17β-estradiol [ES]), TAM or fulvestrant [FUL], aka ICI 182,780) for 6-14 days. Kinetic Image Cytometry™ (KIC™) methods were developed to quantify spontaneously occurring intracellular calcium transients representing the activity of the neurons, and high-content analysis (HCA) methods were developed to quantify the expression, colocalization, and puncta formed by synaptic proteins (postsynaptic density protein-95 [PSD-95] and presynaptic protein Synapsin-1 [Syn-1]). As quantified by KIC, FSK increased the occurrence and synchronization of the calcium transients indicating stimulatory effects on RHN activity, whereas TAM had inhibitory effects. As quantified by HCA, FSK also increased PSD-95 puncta and PSD-95:Syn-1 colocalization, whereas ES increased the puncta of both PSD-95 and Syn-1 with little effect on colocalization. The estrogen receptor antagonist FUL also increased PSD-95 puncta. In contrast, TAM reduced Syn-1 and PSD-95:Syn-1 colocalization, consistent with its inhibitory effects on the calcium transients. Thus TAM reduced activity and synapse formation by the RHNs, which may relate to the ability of this agent to cause PCCI. The results illustrate that KIC and HCA can be used to quantify neurotoxic and neuroprotective effects of chemicals in RHNs to investigate mechanisms and potential therapeutics for PCCI.

Screening the ToxCast phase II libraries for alterations in network function using cortical neurons grown on multi-well microelectrode array (mwMEA) plates

Methods are needed for rapid screening of environmental compounds for neurotoxicity, particularly ones that assess function. To demonstrate the utility of microelectrode array (MEA)-based approaches as a rapid neurotoxicity screening tool, 1055 chemicals from EPA's phase II ToxCast library were evaluated for effects on neural function and cell health. Primary cortical networks were grown on multi-well microelectrode array (mwMEA) plates. On day in vitro 13, baseline activity (40 min) was recorded prior to exposure to each compound (40 µM). Changes in spontaneous network activity [mean firing rate (MFR)] and cell viability (lactate dehydrogenase and CellTiter Blue) were assessed within the same well following compound exposure. Following exposure, 326 compounds altered (increased or decreased) normalized MFR beyond hit thresholds based on 2× the median absolute deviation of DMSO-treated wells. Pharmaceuticals, pesticides, fungicides, chemical intermediates, and herbicides accounted for 86% of the hits. Further, changes in MFR occurred in the absence of cytotoxicity, as only eight compounds decreased cell viability. ToxPrint chemotype analysis identified several structural domains (e.g., biphenyls and alkyl phenols) significantly enriched with MEA actives relative to the total test set. The top 5 enriched ToxPrint chemotypes were represented in 26% of the MEA hits, whereas the top 11 ToxPrints were represented in 34% of MEA hits. These results demonstrate that large-scale functional screening using neural networks on MEAs can fill a critical gap in assessment of neurotoxicity potential in ToxCast assay results. Further, a data-mining approach identified ToxPrint chemotypes enriched in the MEA-hit subset, which define initial structure-activity relationship inferences, establish potential mechanistic associations to other ToxCast assay endpoints, and provide working hypotheses for future studies.

Cognitive impairment following hormone therapy: current opinion of research in breast and prostate cancer patients

PURPOSE OF REVIEW

Hormone therapy is a common cancer treatment that may be associated with numerous side and late effects, and in recent years, has been linked to changes in cognition. Here, we present the most important recent findings from empirical studies and reviews that have focused on the effects of hormone therapy on cognitive functioning in breast and prostate cancer populations, underline some general shortcomings, and propose directions for future research.

RECENT FINDINGS

Recent research indicates that cognitive impairment may occur in breast and prostate cancer patients following onset of hormone therapy. However, because of methodological shortcomings and heterogeneity of current research, conclusions regarding the effects of hormone therapy on cognitive functions remain tentative.

SUMMARY

The review highlights the general findings while also describing the many methodological shortcomings that need to be addressed in future research. It is clear that larger scale neuropsychological studies that also evaluate the impact of impairments on daily life functioning will improve our understanding of the effects of hormone therapy on cognition and inform the development of appropriate interventions.

The Working Memory and Dorsolateral Prefrontal-Hippocampal Functional Connectivity Changes in Long-Term Survival Breast Cancer Patients Treated with Tamoxifen

BACKGROUND

Tamoxifen is the most widely used drug for treating patients with estrogen receptor-sensitive breast cancer. There is evidence that breast cancer patients treated with tamoxifen exhibit cognitive dysfunction. However, the underlying neural mechanism remains unclear. The present study aimed to investigate the neural mechanisms underlying working memory deficits in combination with functional connectivity changes in premenopausal women with breast cancer who received long-term tamoxifen treatment.

METHODS

A total of 31 premenopausal women with breast cancer who received tamoxifen and 32 matched healthy control participants were included. The participants completed n-back tasks and underwent resting-state functional magnetic resonance imaging, which measure working memory performance and brain functional connectivity, respectively. A seed-based functional connectivity analysis within the whole brain was conducted, for which the dorsolateral prefrontal cortex was chosen as the seed region.

RESULTS

Our results indicated that the tamoxifen group had significant deficits in working memory and general executive function performance and significantly lower functional connectivity of the right dorsolateral prefrontal cortex with the right hippocampus compared with the healthy controls. There were no significant changes in functional connectivity in the left dorsolateral prefrontal cortex within the whole brain between the tamoxifen group and healthy controls. Moreover, significant correlations were found in the tamoxifen group between the functional connectivity strength of the dorsolateral prefrontal cortex with the right hippocampus and decreased working memory performance.

CONCLUSION

This study demonstrates that the prefrontal cortex and hippocampus may be affected by tamoxifen treatment, supporting an antagonistic role of tamoxifen in the long-term treatment of breast cancer patients.

Effects of Tibolone on the Central Nervous System: Clinical and Experimental Approaches

Hormone replacement therapy (HRT) increases the risk of endometrial and breast cancer. A strategy to reduce this incidence is the use of tibolone (TIB). The aim of this paper was to address the effects of TIB on the central nervous system (CNS). For the present review, MEDLINE (via PubMed), LILACS (via BIREME), Ovid Global Health, SCOPUS, Scielo, and PsycINFO (ProQuest Research Library) electronic databases were searched for the results of controlled clinical trials on peri- and postmenopausal women published from 1990 to September 2016. Also, this paper reviews experimental studies performed to analyze neuroprotective effects, cognitive deficits, neuroplasticity, oxidative stress, and stroke using TIB. Although there are few studies on the effect of this hormone in the CNS, it has been reported that TIB decreases lipid peroxidation levels and improves memory and learning. TIB has important neuroprotective effects that could prevent the risk of neurodegenerative diseases in postmenopausal women as well as the benefits of HRT in counteracting hot flashes, improving mood, and libido. Some reports have found that TIB delays cognitive impairment in various models of neuronal damage. It also modifies brain plasticity since it acts as an endocrine modulator regulating neurotransmitters, Tau phosphorylation, and decreasing neuronal death. Finally, its antioxidant effects have also been reported in different animal models.

Impairment of the executive attention network in premenopausal women with hormone receptor-positive breast cancer treated with tamoxifen

Tamoxifen (TAM) is most commonly prescribed for patients with hormone-sensitive breast cancer and exerts agonistic/antagonistic effects on estrogen receptors throughout the body. Accumulating evidence has revealed that breast cancer patients receiving TAM manifest cognitive dysfunction. However, whether these patients have a global attention deficit or a more selective impairment of specific attention networks remains unknown. In the present study, we sought to explore the attention function of premenopausal women with hormone receptor-positive breast cancer treated with TAM using the attention network test (ANT). The subjects included breast cancer patients receiving TAM (TAM, N=43), breast cancer patients not receiving TAM (non-TAM, N=41), and matched healthy controls (HC, N=46). The subjects completed the ANT and neuropsychological tests, which measure three independent attention networks and executive function performance, respectively. Our results indicated that patients in the TAM group had significant deficits in their executive control component but not in the alerting or orienting components. Moreover, the patients showed poor executive function performance in the neuropsychological tests. Additionally, in the TAM group, significant correlations were found between the decreased efficiency of the executive control component and their reduced performance in executive function tests. This study demonstrates that premenopausal women with hormone receptor-positive breast cancer treated with TAM have impairment of the executive attention network and that this impairment was associated with differences in executive function performance.

Can Exercise Ameliorate Aromatase Inhibitor-Induced Cognitive Decline in Breast Cancer Patients?

Aromatase inhibitors (AIs) have been commonly used as an effective adjuvant therapy in treatment of breast cancer, especially for menopausal women with estrogen receptor-positive breast cancer. Due to the nature of aromatase, the key enzyme for endogenous estrogen synthesis, inhibitory of aromatase-induced side effects, such as cognitive impairment has been reported in both human and animal studies. While extensive evidence suggested that physical exercises can improve learning and memory activity and even prevent age-related cognitive decline, basic research revealed some common pathways between exercise and estrogen signaling that affected cognitive function. This review draws on clinical and basic studies to assess the potential impact of exercise in cognitive function from women treated with AIs for breast cancer and explore the potential mechanism and effects of exercise on estrogen-related cognition.

Adjuvant ovarian function suppression and cognitive function in women with breast cancer

BACKGROUND

To examine the effect on cognitive function of adjuvant ovarian function suppression (OFS) for breast cancer.

METHODS

The Suppression of Ovarian Function (SOFT) trial randomised premenopausal women with hormone receptor-positive breast cancer to 5 years adjuvant endocrine therapy with tamoxifen+OFS, exemestane+OFS or tamoxifen alone. The Co-SOFT substudy assessed objective cognitive function and patient reported outcomes at randomisation (T0), and 1 year later (T1); the primary endpoint was change in global cognitive function, measured by the composite objective cognitive function score. Data were compared for the pooled tamoxifen+OFS and exemestane+OFS groups vs the tamoxifen alone group using the Wilcoxon rank-sum test.

RESULTS

Of 86 participants, 74 underwent both T0 and T1 cognitive testing; 54 randomised to OFS+ either tamoxifen (28) or exemestane (26) and 20 randomised to tamoxifen alone. There was no significant difference in the changes in the composite cognitive function scores between the OFS+ tamoxifen or exemestane groups and the tamoxifen group (mean±s.d., -0.21±0.92 vs -0.04±0.49, respectively, P=0.71, effect size=-0.20), regardless of prior chemotherapy status, and adjusting for baseline characteristics.

CONCLUSIONS

The Co-SOFT study, although limited by small samples size, provides no evidence that adding OFS to adjuvant oral endocrine therapy substantially affects global cognitive function.

Cancer and Dementia: It's Complicated

The relationship between dementia and cancer is complex. A wealth of observational data suggest (1) reduced risk of certain cancers in Alzheimer and Parkinson diseases; and (2) increased risk of other cancers in Parkinson disease. These relationships persist despite correcting for reporting artifacts and survival bias. Several potential mechanisms have been proposed and warrant further investigation. Aging is a risk factor for both. Common environmental exposures, such as smoking, may play roles. Common mechanisms such as chronic inflammation and immunosenescence, and common risk factors such as diabetes and obesity, have been implicated. Shared genetic pathways are a major focus, particularly those favoring apoptosis and cell proliferation at opposite ends of the spectrum. To complicate the picture further, certain cancer chemotherapy and adjuvant therapy agents have neurotoxic effects, whereas animal studies show other cancer drugs reducing neurodegeneration, raising the possibility of repurposing those agents for use in Alzheimer disease. These multiple potential lines of evidence must be disentangled to investigate underlying mechanisms, the end-game being to develop and to test potential prevention and treatment strategies.

Post-treatment Neurocognition and Psychosocial Care Among Breast Cancer Survivors

INTRODUCTION

Chemotherapy for breast cancer has been associated with cognitive problems; however, the impact of adjuvant hormone therapy is less clear. No studies have explored provider discussions about cognitive concerns or factors associated with neurocognitive treatment. This study examined cognitive problems, factors associated with having a provider discussion, and receipt of neurocognitive treatment.

METHODS

Female breast cancer survivors (N=2,537) from the Sister Study and the Two Sister Study who were at least 1 year post-treatment were surveyed in 2012 about their cancer therapies (confirmed by medical records); cognitive concerns; related provider discussions; and neurocognitive treatment. A total of 2,296 women were included in the current 2014 analysis. Extensive covariate information was also ascertained for predictive multivariate models.

RESULTS

The prevalence of self-reported cognitive problems after treatment was 60%. Of those reporting cognitive problems, only 37% had discussed those concerns with a provider and 15% had been treated for cognitive symptoms. The odds of reported cognitive concerns that started during and after treatment were elevated for those who received only hormone therapy and no chemotherapy (OR=1.64, 95% CI=1.15, 2.33); chemotherapy and no hormone therapy (OR=5.63, 95% CI=3.52, 9.00); or both (OR=6.33, 95% CI=4.21, 9.54) compared with those reporting neither treatment.

CONCLUSIONS

The high prevalence of cognitive concerns underscores the importance of monitoring breast cancer survivors for potential neurocognitive effects of hormone and chemotherapy, discussions with survivors about those concerns, and treatment referrals. Monitoring changes over time can help to evaluate both psychosocial and neurocognitive care provided for survivors.

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.

Tamoxifen induces cellular stress in the nervous system by inhibiting cholesterol synthesis

Background

Tamoxifen (TAM) is an important cancer therapeutic and an experimental tool for effecting genetic recombination using the inducible Cre-Lox technique. Despite its widespread use in the clinic and laboratory, we know little about its effects on the nervous system. This is of significant concern because TAM, via unknown mechanisms, induces cognitive impairment in humans. A hallmark of cellular stress is induction of Activating Transcription Factor 3 (Atf3), and so to determine whether TAM induces cellular stress in the adult nervous system, we generated a knock-in mouse in which Atf3 promoter activity drives transcription of TAM-dependent Cre recombinase (Cre-ERT2); when crossed with tdtomato reporter mice, Atf3 induction results in robust and permanent genetic labeling of cells in which it is up-regulated even transiently.

Results

We found that granular neurons of the olfactory bulb and dentate gyrus, vascular cells and ependymal cells throughout the brain, and peripheral sensory neurons expressed tdtomato in response to TAM treatment. We also show that TAM induced Atf3 up-regulation through inhibition of cholesterol epoxide hydrolase (ChEH): reporter expression was mitigated by delivery in vitamin E-rich wheat germ oil (vitamin E depletes ChEH substrates), and was partially mimicked by a ChEH-specific inhibitor.

Conclusions

This work demonstrates that TAM stresses cells of the adult central and peripheral nervous systems and highlights concerns about clinical and experimental use of TAM. We propose TAM administration in vitamin E-rich vehicles such as wheat germ oil as a simple remedy.

Monitoring and optimising cognitive function in cancer patients: Present knowledge and future directions

The potentially detrimental effects of cancer and related treatments on cognitive functioning are emerging as a key focus of cancer survivorship research. Many patients with central nervous system (CNS) or non-CNS tumours develop cognitive problems during the course of their disease that can result in diminished functional independence. We review the state of knowledge on the cognitive functioning of patients with primary and secondary brain tumours at diagnosis, during and after therapy, and discuss current initiatives to diminish cognitive decline in these patients. Similarly, attention is paid to the cognitive sequelae of cancer and cancer therapies in patients without CNS disease. Disease and treatment effects on cognition are discussed, as well as current insights into the neural substrates and the mechanisms underlying cognitive dysfunction in these patients. In addition, rehabilitation strategies for patients with non-CNS disease confronted with cognitive dysfunction are described. Special attention is given to knowledge gaps in the area of cancer and cognition, in CNS and non-CNS diseases. Finally, we point to the important role for cooperative groups to include cognitive endpoints in clinical trials in order to accelerate our understanding and treatment of cognitive dysfunction related to cancer and cancer therapies.

Long-term subjective cognitive functioning following adjuvant systemic treatment: 7-9 years follow-up of a nationwide cohort of women treated for primary breast cancer

Background:

There is growing concern among breast cancer (BC) patients and survivors about cognitive impairment following systemic treatments. The aim of the present study was to investigate the long-term effects of standard systemic adjuvant therapies on subjective cognitive impairment (SCI) in a large nationwide cohort of BC survivors 7–9 years after primary surgery.

Methods:

Participants were recruited from the nationwide Psychosocial Factors and Breast Cancer inception cohort of Danish women treated for primary BC. SCI was assessed with the Cognitive Failures Questionnaire and women allocated to systemic treatment according to nationwide standard protocols were compared with women who had not received any systemic treatments.

Results:

A total of 1889 recurrence-free survivors were eligible for analysis. No difference in SCI was found between survivors across standardized systemic treatment protocols when analyses were stratified by menopausal status and adjusted for possible sociodemographic and treatment-related confounders. The frequency of significant SCI in a subgroup of survivors in the age range 65–74 years was ∼7%.

Conclusions:

No differences in long-term SCI at 7–9 years post surgery were found between women who had received systemic therapies and those who had not. Furthermore, the observed proportion of survivors with significant SCI was comparable to normative data. These results are important to communicate to patients, survivors, and clinicians alike, especially in the light of increasing concern about cognitive impairment following systemic therapies.

Cognitive function after the initiation of adjuvant endocrine therapy in early-stage breast cancer: an observational cohort study

PURPOSE

This report examines cognitive complaints and neuropsychological (NP) testing outcomes in patients with early-stage breast cancer after the initiation of endocrine therapy (ET) to determine whether this therapy plays any role in post-treatment cognitive complaints.

PATIENTS AND METHODS

One hundred seventy-three participants from the Mind Body Study (MBS) observational cohort provided data from self-report questionnaires and NP testing obtained at enrollment (T1, before initiation of ET), and 6 months later (T2). Bivariate analyses compared demographic and treatment variables, cognitive complaints, depressive symptoms, quality of life, and NP functioning between those who received ET versus not. Multivariable linear regression models examined predictors of cognitive complaints at T2, including selected demographic variables, depressive symptoms, ET use, and other medical variables, along with NP domains that were identified in bivariate analyses.

RESULTS

Seventy percent of the 173 MBS participants initiated ET, evenly distributed between tamoxifen or aromatase inhibitors. ET-treated participants reported significantly increased language and communication (LC) cognitive complaints at T2 (P = .003), but no significant differences in NP test performance. Multivariable regression on LC at T2 found higher LC complaints significantly associated with T1 LC score (P < .001), ET at T2 (P = .004), interaction between ET and past hormone therapy (HT) (P < .001), and diminished improvement in NP psychomotor function (P = .05). Depressive symptoms were not significant (P = .10).

CONCLUSION

Higher LC complaints are significantly associated with ET 6 months after starting treatment and reflect diminished improvements in some NP tests. Past HT is a significant predictor of higher LC complaints after initiation of ET.

Decision-making impairments in breast cancer patients treated with tamoxifen

The selective estrogen receptor modulator tamoxifen (TAM) is most commonly prescribed for patients with hormone-sensitive breast cancer. Although TAM can bind to estrogen receptors in the nervous system, it is unknown whether it acts as an estrogen agonist or antagonist in the human brain. Several studies have reported the negative effects of TAM on cognitive function; however, its effects on decision-making function have not been previously explored. The present study aimed to investigate the decision-making function under ambiguity and risk in breast cancer patients treated with TAM. Participants included breast cancer patients taking TAM (TAM, n=47) and breast cancer patients not taking TAM (non-TAM, n=45) as well as their matched healthy controls (HC, n=50). All participants were given the Iowa Gambling Task (IGT) to assess their decision-making under conditions involving ambiguity, the Game of Dice Task (GDT) to assess their decision-making under conditions involving risk, and a battery of neuropsychological tests. Our results indicated that patients in the TAM group were significantly impaired as assessed by both the IGT and GDT and performed significantly worse on some aspects of various tasks involving memory and information processing. Furthermore, we found that decreased performance on verbal memory testing significantly correlated with IGT performance, and executive dysfunction was associated with poor GDT performance in breast cancer patients undergoing TAM treatment. This study demonstrates that breast cancer patients taking TAM have several decision-making impairments. These findings may support the idea that TAM resulting in cognitive changes plays an antagonistic role in the areas of the brain where estrogen receptors are present, including the prefrontal cortex, hippocampus and amygdala.

Monitoring and optimising cognitive function in cancer patients: Present knowledge and future directions

The potentially detrimental effects of cancer and related treatments on cognitive functioning are emerging as a key focus of cancer survivorship research. Many patients with central nervous system (CNS) or non-CNS tumours develop cognitive problems during the course of their disease that can result in diminished functional independence. We review the state of knowledge on the cognitive functioning of patients with primary and secondary brain tumours at diagnosis, during and after therapy, and discuss current initiatives to diminish cognitive decline in these patients. Similarly, attention is paid to the cognitive sequelae of cancer and cancer therapies in patients without CNS disease. Disease and treatment effects on cognition are discussed, as well as current insights into the neural substrates and the mechanisms underlying cognitive dysfunction in these patients. In addition, rehabilitation strategies for patients with non-CNS disease confronted with cognitive dysfunction are described. Special attention is given to knowledge gaps in the area of cancer and cognition, in CNS and non-CNS diseases. Finally, we point to the important role for cooperative groups to include cognitive endpoints in clinical trials in order to accelerate our understanding and treatment of cognitive dysfunction related to cancer and cancer therapies.

A four week randomised control trial of adjunctive medroxyprogesterone and tamoxifen in women with mania

Emerging research has suggested that hormone treatments such as selective oestrogen receptor modulators (SERMs) or progestins may be useful in the treatment of mania. The current pilot study compared the use of the SERM tamoxifen and the progestin medroxyprogesterone acetate (MPA), as an adjunct to mood stabiliser medications, for the treatment of mania symptoms in 51 women in a 28-day double blind, placebo controlled study. The primary outcome was the change between baseline and day 28 mania scores as measured by the Clinician Administered Rating Scale for Mania (CARS-M). Adjunctive MPA treatment provided greater and more rapid improvement in mania symptoms compared with adjunctive placebo and tamoxifen treatment. Adjunctive therapy with MPA may be a potentially useful new treatment for persistent mania, leading to a greater and more rapid resolution of symptoms compared with mood stabiliser treatment alone.

Steroid receptor coactivator-1: a versatile regulator and promising therapeutic target for breast cancer

Breast cancer is the leading cause of cancer death for women worldwide. Various therapeutic approaches have been proposed, among which endocrine therapy has recently become popular due to the high sensitivity of breast tissues to steroids such as estrogens and progesterone. The underlying mechanisms of steroid regulation in breast cancer cell proliferation, invasiveness, metastasis and endocrine resistance, however, remain largely unknown. Steroid receptor coactivator-1 (SRC-1) has attracted much attention because it is an important co-regulator and plays a pivotal role in modulating the transcriptional activities of steroid nuclear receptors. Accumulated research has established a strong correlation between SRC-1 and the pathological progression or disease-related features of breast cancer, which supports its potential as a target for specific therapeutic intervention in the clinical management of breast cancer. In addition, a diverse group of downstream molecules have also been shown to participate in various functional pathways related to SRC-1-associated regulation of breast cancer. These downstream molecules are also considered promising therapeutic targets, providing additional options for targeted treatments. In this review, the expression of SRC-1 in breast cancer and the close relationships between SRC-1 and the cell proliferation, invasiveness, metastasis and endocrine resistance of breast cancer will be discussed, followed by a brief summary of its putative functional mechanisms with an emphasis on the potential therapeutic role of SRC-1.