Effects of physical exercise during adjuvant chemotherapy for breast cancer on long-term tested and perceived cognition: results of a pragmatic follow-up study.

PURPOSE: Cancer-related cognitive impairment (CRCI) following chemotherapy is commonly reported in breast cancer survivors, even years after treatment. Data from preclinical studies suggest that exercise during chemotherapy may prevent or diminish cognitive problems; however, clinical data are scarce. METHODS: This is a pragmatic follow-up study of two original randomized trials, which compares breast cancer patients randomized to exercise during chemotherapy to non-exercise controls 8.5 years post-treatment. Cognitive outcomes include an online neuropsychological test battery and self-reported cognitive complaints. Cognitive performance was compared to normative data and expressed as age-adjusted z-scores. RESULTS: A total of 143 patients participated in the online cognitive testing. Overall, cognitive performance was mildly impaired on some, but not all, cognitive domains, with no significant differences between groups. Clinically relevant cognitive impairment was present in 25% to 40% of all participants, regardless of study group. We observed no statistically significant effect of exercise, or being physically active during chemotherapy, on long-term cognitive performance or self-reported cognition, except for the task reaction time, which favored the control group (ß = -2.04, 95% confidence interval: -38.48; -2.38). We observed no significant association between self-reported higher physical activity levels during chemotherapy or at follow-up and better cognitive outcomes. CONCLUSION: In this pragmatic follow-up study, exercising and being overall more physically active during or after adjuvant chemotherapy for breast cancer was not associated with better tested or self-reported cognitive functioning, on average, 8.5 years after treatment. Future prospective studies are needed to document the complex relationship between exercise and CRCI in cancer survivors.

Towards a Clearer Causal Question Underlying the Association Between Cancer and Dementia.

BACKGROUND: Several observational studies have described an inverse association between cancer diagnosis and subsequent dementia risk. Multiple biologic mechanisms and potential biases have been proposed in attempts to explain this association. One proposed explanation is the opposite expression of Pin1 in cancer and dementia, and we use this explanation and potential drug target to illustrate the required assumptions and potential sources of bias for inferring an effect of Pin1 on dementia risk from analyses measuring cancer diagnosis as a proxy for Pin1 expression. METHODS: We used data from the Rotterdam Study, a population-based cohort. We estimate the association between cancer diagnosis (as a proxy for Pin1) and subsequent dementia diagnosis using two different proxy methods and with confounding and censoring for death addressed with inverse probability weights. We estimate and compare the complements of a weighted Kaplan-Meier survival estimator at 20 years of follow-up. RESULTS: Out of 3634 participants, 899 (25%) were diagnosed with cancer, of whom 53 (6%) had dementia, and 567 (63%) died. Among those without cancer, 15% (411) were diagnosed with dementia, and 667 (24%) died over follow-up. Depending on the confounding and selection bias control, and the way in which cancer was used as a time-varying proxy exposure, the risk ratio for dementia diagnosis ranged from 0.71 (95% confidence interval [CI] = 0.49, 0.95) to 1.1 (95% CI = 0.79, 1.3). CONCLUSION: Being explicit about the underlying mechanism of interest is key to maximizing what we can learn from this cancer-dementia association given available or readily collected data, and to defining, detecting, and preventing potential biases.

Effect of Physical Exercise on MRI-Assessed Brain Perfusion in Chemotherapy-Treated Breast Cancer Patients: A Randomized Controlled Trial.

BACKGROUND: Exercise is a promising intervention to alleviate cognitive problems in breast cancer patients, but studies on mechanisms underlying these effects are lacking. PURPOSE: Investigating whether an exercise intervention can affect cerebral blood flow (CBF) in cognitively impaired breast cancer patients and to determine if CBF changes relate to memory function. STUDY TYPE: Prospective. POPULATION: A total of 181 chemotherapy-treated stage I-III breast cancer patients with cognitive problems and relatively low physical activity levels (≤150 minutes moderate to vigorous physical activity per week), divided into an exercise (N = 91) or control group (N = 90). FIELD STRENGTH/SEQUENCE: Two-dimensional echo planar pseudo-continuous arterial spin labeling CBF sequence at 3 T. ASSESSMENT: The 6-month long intervention consisted of (supervised) aerobic and strength training, 4 × 1 hour/week. Measurements at baseline (2-4 years post-diagnosis) and after 6 months included gray matter CBF in the whole brain, hippocampus, anterior cingulate cortex, and posterior cingulate cortex. Physical fitness and memory function were also assessed. Subgroup analyses were performed in patients with high fatigue levels at baseline. STATISTICAL TESTS: Multiple regression analyses with a two-sided alpha of 0.05 for all analyses. RESULTS: There was a significant improvement in physical fitness (VO2peak in mL/minute/kg) in the intervention group (N = 53) compared to controls (N = 51, ß = 1.47 mL/minute/kg, 95% CI: 0.44-2.50). However, no intervention effects on CBF were found (eg, whole brain: P = 0.565). Highly fatigued patients showed larger but insignificant treatment effects on CBF (eg, whole brain: P = 0.098). Additionally, irrespective of group, a change in physical fitness was positively associated with changes in CBF (eg, whole brain: ß = 0.75, 95% CI: 0.07-1.43). There was no significant relation between CBF changes and changes in memory performance. DATA CONCLUSION: The exercise intervention did not affect CBF of cognitively affected breast cancer patients. A change in physical fitness was associated with changes in CBF, but changes in CBF were not associated with memory functioning. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 5.

Long-term effects of premenopausal risk-reducing salpingo-oophorectomy on cognition in women with high familial risk of ovarian cancer: A cross-sectional study.

OBJECTIVE: To examine the effect of a premenopausal risk-reducing salpingo-oophorectomy (RRSO) in women at increased risk of ovarian cancer on objective and subjective cognition at least 10 years after RRSO. DESIGN: A cross-sectional study with prospective follow-up, nested in a nationwide cohort. SETTING: Multicentre in the Netherlands. POPULATION OR SAMPLE: 641 women (66% BRCA1/2 pathogenic variant carriers) who underwent either a premenopausal RRSO ≤ age 45 (n = 436) or a postmenopausal RRSO ≥ age 54 (n = 205). All participants were older than 55 years at recruitment. METHODS: Participants completed an online cognitive test battery and a questionnaire on subjective cognition. We used multivariable regression analyses, adjusting for age, education, breast cancer, hormone replacement therapy, cardiovascular risk factors and depression. MAIN OUTCOME MEASURES: The influence of RRSO on objective and subjective cognition of women with a premenopausal RRSO compared with women with a postmenopausal RRSO. RESULTS: After adjustment, women with a premenopausal RRSO (mean time since RRSO 18.2 years) performed similarly on objective cognitive tests compared with women with a postmenopausal RRSO (mean time since RRSO 11.9 years). However, they more frequently reported problems with reasoning (odds ratio [OR] 1.8, 95% confidence interval [95% CI] 1.1-3.1) and multitasking (OR 1.9, 95% CI 1.1-3.4) than women with a postmenopausal RRSO. This difference between groups disappeared in an analysis restricted to women of comparable ages (60-70 years). CONCLUSIONS: Reassuringly, approximately 18 years after RRSO, we found no association between premenopausal RRSO and objective cognition.

Health-related quality of life after stereotactic radiosurgery in patients with brain metastases.

PURPOSE: This study aimed to assess health-related quality of life (HRQoL) in patients with brain metastases treated with stereotactic radiosurgery (SRS) and to identify factors associated with this. METHODS: HRQoL was measured pre-SRS, at 3- and 6-month follow-up. Physical functioning, cognitive functioning, role functioning, and fatigue were analyzed with the EORTC QLQ-C30 questionnaire. Motor dysfunction, future uncertainty, visual disorder, communication deficit, and headaches were analyzed with the EORTC QLQ-BN20. Clinically important symptom or functional impairment was assessed following set thresholds. Factors associated with impairment were identified through multivariable logistic regression analyses. RESULTS: At baseline, 178 patients were included; 54% (n=96) completed questionnaires at 3 months and 39% (n=70) at 6 months. Before SRS, 29% of linear accelerator (LINAC) patients reported physical and cognitive impairment, while 25% reported impairment for fatigue. At 6 months, 39%, 43%, and 57% of LINAC patients reported impairment respectively. Forty-five percent of Gamma Knife (GK) patients reported impairment pre-SRS for physical, cognitive functioning, and fatigue. At 6 months, 48%, 43%, and 33% of GK patients reported impairment respectively. Except for role functioning, pre-SRS symptom and functioning scores were associated with impairment at 3 months, whereas scores at 3 months were associated with impairment at 6 months. Age, gender, systemic therapy, and intracranial progression were not associated with clinically important impairment. CONCLUSION: As 33-57% of patients with brain metastases reported symptom burden and functional impairments that were of clinical importance, it is recommended to pay attention to the HRQoL outcomes of these patients during clinical encounters.

Establishing General Working Population Norms for the Cognitive Symptom Checklist-Work.

PURPOSE: The Cognitive Symptom Checklist-Work (CSC-W) is a self-report measure to assess cognitive symptoms (i.e., memory and executive function) in working adults with cancer. To date, general working population norm data are lacking worldwide. We established CSC-W norm values in the general working population, and assessed associations of CSC-W scores with work and health-related factors. METHODS: This cross-sectional study consisted of 1,000 Dutch working adults, of whom data was collected through an online respondent panel. The sample was stratified for sex and age, and data were weighted. Summary scores of the CSC-W total scale, and memory and executive function symptoms subscales, were determined (e.g., means, percentiles). Z- and T-scores were calculated, and analysis of (co)variance has been applied. RESULTS: Cognitive symptom scores were relatively stable across age groups, but 18-39-year-old respondents reported lower memory and executive function than respondents in other age groups. Symptom scores of memory function (mean 29.1; SD = 16.7) were higher for all age groups and in both sexes compared to executive function (mean 22.1; SD = 16.8). No sex differences in memory and executive function were observed. Higher symptom scores were associated with performing non-manual work only, manual work only, self-reported long-term illness, and higher levels of depressive symptoms and fatigue. CONCLUSION: The CSC-W norms may enhance the interpretation and facilitate the analysis of self-reported cognitive symptoms in patients with cancer at work. Our findings may support health care professionals in identifying working adults with cancer with cognitive symptoms and in developing personalized treatment.

Neurocognitive functioning after Gamma Knife and LINAC stereotactic radiosurgery in patients with brain metastases.

PURPOSE: Brain metastases (BM) themselves and treatment with stereotactic radiosurgery (SRS) can influence neurocognitive functioning. This prospective study aimed to assess neurocognitive decline in patients with BM after SRS. METHODS: A neuropsychological test battery was assessed yielding ten test outcomes. Neurocognitive decline at 3 and 6 months post SRS was compared to measurement prior to Gamma Knife (GK) or linear accelerator (LINAC) SRS. Reliable change indices with correction for practice effects were calculated to determine the percentage of neurocognitive decline (defined as decline on ≥ 2 test outcomes). Risk factors of neurocognitive decline were analyzed with binary logistic regression. RESULTS: Of 194 patients pre-SRS, 40 GK and 29 LINAC patients had data accessible at 6 months. Compared to baseline, 38% of GK patients declined at 3 months, and 23% declined at 6 months. GK patients declined on attention, executive functioning, verbal memory, and fine motor skill. Of LINAC patients, 10% declined at 3 months, and 24% at 6 months. LINAC patients declined on executive functioning, verbal memory, and fine motor skills. Risk factors of neurocognitive decline at 3 months were high age, low education level and type of SRS (GK or LINAC). At 6 months, high age was a risk factor. Karnofsky Performance Scale, BM volume, number of BM, tumor progression and neurocognitive impairment pre-SRS were no risk factors. CONCLUSION: Neurocognitive decline occurs in a considerable proportion of patients with BM treated with GK or LINAC SRS. Overall, high age appears to be a risk factor for neurocognitive decline after SRS.

Clinical characteristics, pathophysiology, and management of noncentral nervous system cancer-related cognitive impairment in adults.

Answer questions and earn CME/CNE Over the past few decades, a body of research has emerged confirming what many adult patients with noncentral nervous system cancer have long reported-that cancer and its treatment are frequently associated with cancer-related cognitive impairment (CRCI). The severity of CRCI varies, and symptoms can emerge early or late in the disease course. Nonetheless, CRCI is typically mild to moderate in nature and primarily involves the domains of memory, attention, executive functioning, and processing speed. Animal models and novel neuroimaging techniques have begun to unravel the pathophysiologic mechanisms underlying CRCI, including the role of inflammatory cascades, direct neurotoxic effects, damage to progenitor cells, white matter abnormalities, and reduced functional connectivity, among others. Given the paucity of research on CRCI with other cancer populations, this review synthesizes the current literature with a deliberate focus on CRCI within the context of breast cancer. A hypothetical case-study approach is used to illustrate how CRCI often presents clinically and how current science can inform practice. While the literature regarding intervention for CRCI is nascent, behavioral and pharmacologic approaches are discussed.

Fatigue and resting-state functional brain networks in breast cancer patients treated with chemotherapy.

PURPOSE: This longitudinal study aimed to disentangle the impact of chemotherapy on fatigue and hypothetically associated functional brain network alterations. METHODS: In total, 34 breast cancer patients treated with chemotherapy (BCC +), 32 patients not treated with chemotherapy (BCC -), and 35 non-cancer controls (NC) were included. Fatigue was assessed using the EORTC QLQ-C30 fatigue subscale at two time points: baseline (T1) and six months after completion of chemotherapy or matched intervals (T2). Participants also underwent resting-state functional magnetic resonance imaging (rsfMRI). An atlas spanning 90 cortical and subcortical brain regions was used to extract time series, after which Pearson correlation coefficients were calculated to construct a brain network per participant per timepoint. Network measures of local segregation and global integration were compared between groups and timepoints and correlated with fatigue. RESULTS: As expected, fatigue increased over time in the BCC + group (p = 0.025) leading to higher fatigue compared to NC at T2 (p = 0.023). Meanwhile, fatigue decreased from T1 to T2 in the BCC - group (p = 0.013). The BCC + group had significantly lower local efficiency than NC at T2 (p = 0.033), while a negative correlation was seen between fatigue and local efficiency across timepoints and all participants (T1 rho = - 0.274, p = 0.006; T2 rho = - 0.207, p = 0.039). CONCLUSION: Although greater fatigue and lower local functional network segregation co-occur in breast cancer patients after chemotherapy, the relationship between the two generalized across participant subgroups, suggesting that local efficiency is a general neural correlate of fatigue.

Long-term effects of adjuvant treatment for breast cancer on carotid plaques and brain perfusion.

PURPOSE: Breast cancer treatment has been associated with vascular pathology. It is unclear if such treatment is also associated with long-term cerebrovascular changes. We studied the association between radiotherapy and chemotherapy with carotid pathology and brain perfusion in breast cancer survivors. METHODS: We included 173 breast cancer survivors exposed to radiotherapy and chemotherapy, assessed ± 21.2 years after cancer diagnosis, and 346 age-matched cancer-free women (1:2) selected from the population-based Rotterdam Study. Outcome measures were carotid plaque score, intima-media thickness (IMT), total cerebral blood flow (tCBF), and brain perfusion. Additionally, we investigated the association between inclusion of the carotid artery in the radiation field (no/small/large part), tumor location, and these outcome measures within cancer survivors. RESULTS: Cancer survivors had lower tCBF (- 19.6 ml/min, 95%CI - 37.3;- 1.9) and brain perfusion (- 2.5 ml/min per 100 ml, 95%CI - 4.3;- 0.7) than cancer-free women. No statistically significant group differences were observed regarding plaque score or IMT. Among cancer survivors, a large versus a small part of the carotid artery in the radiation field was associated with a higher IMT (0.05, 95%CI0.01;0.09). Also, survivors with a right-sided tumor had lower left carotid plaque score (- 0.31, 95%CI - 0.60;- 0.02) and higher brain perfusion (3.5 ml/min per 100 ml, 95%CI 0.7;6.2) than those with a left-sided tumor. CONCLUSIONS: On average two decades post-diagnosis, breast cancer survivors had lower tCBF and brain perfusion than cancer-free women. Also, survivors with a larger area of the carotid artery within the radiation field had a larger IMT. Future studies should confirm if these cerebrovascular changes underlie the frequently observed cognitive problems in cancer survivors.

Prevalence of cognitive impairment and change in patients with breast cancer: A systematic review of longitudinal studies.

OBJECTIVE: Patients with breast cancer face cognitive impairment that affects their quality of life; partially attributable to treatment. Our aim was to detail the prevalence and change of cognitive impairment during the course of treatment. We also investigated the effect of therapy (chemotherapy [CT]) vs. radiotherapy and/or endocrine therapy vs. healthy controls). METHODS: This article reviews longitudinal cohort studies published to date in Medline and Embase that (i) assess cognition before and after therapy, (ii) report prevalence cognitive impairment or change, and (iii) use standardized and valid neuropsychological tests. We used the original authors' criteria for cognitive impairment. RESULTS: The title and abstract of 891 articles were screened, resulting in the identification of 90 potentially relevant articles while applying the eligibility criteria. After full-text examination, 17 studies were included. Prevalence of cognitive impairment range from 25% before therapy, through 24% after therapy to 21% at maximal 1-year follow-up (FU). Compared to their pretreatment cognitive functioning, 24% of patients decline after treatment and 24% at 1-year FU. Some studies also reported cognitive improvement showing that 15% and 31% of patients improve, respectively. In general, patients undergoing CT have a higher chance of cognitive impairment and decline than no-CT patients and healthy controls. CONCLUSIONS: This study shows that one out of four breast cancer patients shows cognitive impairment prior to treatment administration CT and a significant number of patients decline during the course of disease, suggesting that cognitive impairment is not exclusively related to CT and/or no-CT therapies. This study shows that assessment of cognitive functioning, ideally over time, is crucial and may help the implementation of personalized rehabilitation pathways.

Change in cognition before and after non-central nervous system cancer diagnosis: A population-based cohort study.

OBJECTIVE: Clinical studies showing that non-central nervous system cancer patients can develop cognitive impairment have primarily focused on patients with specific cancer types and intensive treatments. To better understand the course of cognitive function in the general population of cancer patients, we assessed cognitive trajectories of patients before and after cancer diagnosis in a population-based setting. METHODS: Between 1989 and 2014, 2211 participants from the population-based Rotterdam study had been diagnosed with cancer of whom 718 (32.5%) had undergone ≥1 cognitive assessment before and after diagnosis. Cognition was measured every 3 to 6 years using a neuropsychological battery. Linear mixed models were used to compare cognitive trajectories of patients before and after diagnosis with those of age-matched cancer-free controls (1:3). RESULTS: Median age at cancer diagnosis was 70.3 years and 47.1% were women. Most patients (68.1%) had received local treatment only. Cognitive trajectories of patients before and after cancer diagnosis were largely similar to those of controls. After diagnosis, the largest difference was found on a memory test (patients declined with 0.14 units per year on the Word Learning Test: delayed recall [95% CI = -0.35; 0.07] and controls with 0.09 units [95% CI = -0.18;-0.00], p for difference = .59). CONCLUSIONS: In this longitudinal cohort, cancer did not appear to alter the trajectory of change in cognitive test results over time from that seen in similar individuals without cancer, although most cancer patients did not receive systemic therapies. Future studies should focus on identifying subgroups of patients who are at high risk for developing cognitive impairment.

Ascertainment of cancer in longitudinal research: The concordance between the Rotterdam Study and the Netherlands Cancer Registry.

Complete and accurate registration of cancer is needed to provide reliable data on cancer incidence and to investigate aetiology. Such data can be derived from national cancer registries, but also from large population-based cohort studies. Yet, the concordance and discordance between these two data sources remain unknown. We evaluated completeness and accuracy of cancer registration by studying the concordance between the population-based Rotterdam Study (RS) and the Netherlands Cancer Registry (NCR) between 1989 and 2012 using the independent case ascertainment method. We compared all incident cancers in participants of the RS (aged ≥45 years) to registered cancers in the NCR in the same persons based on the date of diagnosis and the International Classification of Diseases (ICD) code. In total, 2,977 unique incident cancers among 2,685 persons were registered. Two hundred eighty-eight cancers (9.7%) were coded by the RS that were not present in the NCR. These were mostly nonpathology-confirmed lung and haematological cancers. Furthermore, 116 cancers were coded by the NCR, but not by the RS (3.9%), of which 20.7% were breast cancers. Regarding pathology-confirmed cancer diagnoses, completeness was >95% in both registries. Eighty per cent of the cancers registered in both registries were coded with the same date of diagnosis and ICD code. Of the remaining cancers, 344 (14.5%) were misclassified with regard to date of diagnosis and 72 (3.0%) with regard to ICD code. Our findings indicate that multiple sources on cancer are complementary and should be combined to ensure reliable data on cancer incidence.

Pathology-confirmed versus non pathology-confirmed cancer diagnoses: incidence, participant characteristics, and survival.

Cancer diagnoses which are not confirmed by pathology are often under-registered in cancer registries compared to pathology-confirmed diagnoses. It is unknown how many patients have a non pathology-confirmed cancer diagnosis, and whether their characteristics and survival differ from patients with a pathology-confirmed diagnosis. Participants from the prospective population-based Rotterdam Study were followed between 1989 and 2013 for the diagnosis of cancer. Cancer diagnoses were classified into pathology-confirmed versus non pathology-confirmed (i.e., based on imaging or tumour markers). We compared participant characteristics and the distribution of cancers at different sites. Furthermore, we investigated differences in overall survival using survival curves adjusted for age and sex. During a median (interquartile range) follow-up of 10.7 (6.3-15.9) years, 2698 out of 14,024 participants were diagnosed with cancer, of which 316 diagnoses (11.7%) were non pathology-confirmed. Participants with non pathology-confirmed diagnoses were older, more often women, and had a lower education. Most frequently non pathology-confirmed cancer sites included central nervous system (66.7%), hepato-pancreato-biliary (44.5%), and unknown primary origin (31.2%). Survival of participants with non pathology-confirmed diagnoses after 1 year was lower compared to survival of participants with pathology-confirmed diagnoses (32.6% vs. 63.4%; risk difference of 30.8% [95% CI 25.2%; 36.2%]). Pathological confirmation of cancer is related to participant characteristics and cancer site. Furthermore, participants with non pathology-confirmed diagnoses have worse survival than participants with pathology-confirmed diagnoses. Missing data on non pathology-confirmed diagnoses may result in underestimation of cancer incidence and in an overestimation of survival in cancer registries, and may introduce bias in aetiological research.

Balance between innate versus adaptive immune system and the risk of dementia: a population-based cohort study.

BACKGROUND: Immunity has been suggested to be important in the pathogenesis of dementia. However, the contribution of innate versus adaptive immunity in the development of dementia is not clear. In this study, we aimed to investigate (1) the association between components of innate immunity (granulocytes and platelets) and adaptive immunity (lymphocytes) with risk of dementia and (2) the association between their derived ratios (granulocyte-to-lymphocyte ratio [GLR], platelet-to-lymphocyte ratio [PLR], and systemic immune-inflammation index [SII]), reflecting the balance between innate and adaptive immunity, with risk of dementia. METHODS: Blood cell counts were measured repeatedly between 2002 and 2015 in dementia-free participants of the prospective population-based Rotterdam Study. Participants were followed-up for dementia until 1 January 2016. Joint models were used to determine the association between granulocyte, platelets, and lymphocyte counts, and their derived ratios with risk of dementia. RESULTS: Of the 8313 participants (mean [standard deviation] age 61.1 [7.4] years, 56.9% women), 664 (8.0%) developed dementia during a median follow-up of 8.6 years. Doubling of granulocyte and platelet counts tended to be associated with an increased risk of dementia (HR [95%CI] 1.22 [0.89-1.67] and 1.45 [1.07-1.95], respectively). Doubling of the derived ratios GLR, PLR, and SII were all associated with an increased dementia risk (HR [95%CI] 1.26 [1.03-1.53], 1.27 [1.05-1.53], and 1.15 [0.98-1.34], respectively). CONCLUSIONS: GLR, PLR, and SII are associated with an increased risk of dementia in the general population. This supports the role of an imbalance in the immune system towards innate immunity in the pathogenesis of dementia.

Interventions for cognitive problems in adults with brain cancer: A narrative review.

INTRODUCTION: Many patients with brain cancer experience cognitive problems. In this narrative review, we comprehensively evaluated empirical studies on various intervention approaches for cognitive problems in these patients. METHODS: Intervention studies that reported effects on cognitive functioning (either objectively tested or subjectively reported) in adult patients with primary and/or secondary brain tumours were identified through online searches in PubMed (MEDLINE) and Web of Science up to 13 March 2019. RESULTS: Of the 364 identified records, 10 pharmacological (including five randomised placebo-controlled trials), 10 cognitive rehabilitation (including five [pilot] RCTs) and two multiple-group exercise studies matched the inclusion criteria. Seventeen of 22 studies had final sample sizes smaller than 40. Several cognitive rehabilitation studies and some pharmacological approaches (donepezil and memantine) showed (at least partial) benefits for cognitive problems in adults with brain cancer. The effects of other pharmacological and exercise interventions were inconclusive and/or preliminary. CONCLUSION: Overall, drawing firm conclusions is complicated due to various methodological shortcomings, including the absence of a (placebo) control group and small sample sizes. Promising effects have been reported for cognitive rehabilitation and some pharmacological approaches. Suggestions for more thorough research with respect to the various approaches are provided.

Inflammation markers and cognitive performance in breast cancer survivors 20 years after completion of chemotherapy: a cohort study.

BACKGROUND: Inflammation is an important candidate mechanism underlying cancer and cancer treatment-related cognitive impairment. We investigated levels of blood cell-based inflammatory markers in breast cancer survivors on average 20 years after chemotherapy and explored the relation between these markers and global cognitive performance. METHODS: One hundred sixty-six breast cancer survivors who received post-surgical radiotherapy and six cycles of adjuvant cyclophosphamide, methotrexate, and fluorouracil (CMF) chemotherapy on average 20 years before enrollment were compared with 1344 cancer-free women from a population-based sample (50-80 years old). Breast cancer survivors were excluded if they used adjuvant hormonal therapy or if they developed relapse, metastasis, or second primary malignancies. Systemic inflammation status was assessed by the granulocyte-to-lymphocyte ratio (GLR), platelet-to-lymphocyte ratio (PLR), and systemic immune-inflammation index (SII). Cognitive performance was assessed using an extensive neuropsychological test battery from which the general cognitive factor was derived to evaluate global cognitive performance. We examined the association between cancer, the general cognitive factor, and inflammatory markers using linear regression models. RESULTS: Breast cancer survivors had a lower general cognitive factor than non-exposed participants from the comparator group (mean difference = -0.21; 95% confidence interval (CI) -0.35 to -0.06). Inflammatory markers were higher in cancer survivors compared with non-exposed participants (mean difference for log(GLR) = 0.31; 95% CI 0.24 to 0.37, log(PLR) = 0.14; 95% CI 0.09 to 0.19, log(SII) = 0.31; 95% CI 0.24 to 0.39). The association between higher levels of inflammatory markers and lower general cognitive factor was statistically significant in cancer survivors but not among non-exposed participants. We found a group-by-inflammatory marker interaction; cancer survivors showed additional lower general cognitive factor per standard deviation increase in inflammatory markers (P for interaction for GLR = 0.038, PLR = 0.003, and SII = 0.033). CONCLUSIONS: This is the first study to show that (1) cancer survivors have increased levels of inflammation on average 20 years after treatment and (2) these inflammatory levels are associated with lower cognitive performance. Although this association needs verification by a prospective study to determine causality, our findings can stimulate research on the role of inflammation in long-term cognitive problems and possibilities to diminish such problems.

Cancer and dementia: Two sides of the same coin?

Noncentral nervous system cancer and the brain share an interesting and complex relation, with an emerging body of evidence showing that cancer patients are at an increased risk of developing cognitive problems. In contrast, population-based studies consistently find an inverse link between cancer and dementia, that is patients with dementia having a lower risk of subsequently developing cancer, and cancer patients being less often diagnosed with dementia. Different biological processes such as inversely activated cell proliferation and survival pathways have been suggested to have an important role underlying this inverse association. However, the effect of methodological biases including surveillance or survival bias has not been completely ruled out, calling into question the inverse direction of the association between cancer and dementia. In fact, emerging evidence now suggests that cancer and dementia might share a positive association. This narrative review summarises the current literature on cancer, cognitive problems and dementia. Moreover, different strategies will be discussed to reduce the impact of potential methodological biases on the association between cancer and dementia, trying to reveal the true direction of this link.

Mild Cognitive Impairment and Dementia Show Contrasting Associations with Risk of Cancer.

BACKGROUND: To investigate and to compare the relation between dementia and cancer with the association between mild cognitive impairment (MCI) and cancer. METHODS: A total of 13,207 persons from the Rotterdam Study were followed between 1990 and 2013 for the onset of dementia and cancer (sample 1). Between 2002 and 2005, a subset of 5,181 persons underwent extensive cognitive testing for MCI and subsequently were followed up for cancer until 2013 (sample 2). We used Cox proportional hazard models to determine the association between dementia and cancer, and MCI and cancer. RESULTS: In sample 1, 1,404 patients were diagnosed with dementia, and 2,316 developed cancer (63 among dementia cases). Dementia was associated with a decreased risk of cancer (hazard ratio [HR] 0.53; 95% CI 0.41-0.68). In sample 2, 513 persons were diagnosed with MCI and 670 persons developed cancer (81 among MCI cases). In contrast to individuals with dementia, those with MCI tended to have an increased risk of cancer (HR 1.25; 95% CI 0.99-1.58). CONCLUSIONS: We found that persons with MCI tended to have an increased risk of cancer, whereas those with dementia have a decreased risk. These findings call into question a biological explanation for the inverse link between dementia and cancer, thereby suggesting the presence of methodological bias.