Prediction of gastrointestinal symptoms trajectories using omega-3 and inflammatory biomarkers in early-stage breast cancer patients receiving chemotherapy

PURPOSE

Gastrointestinal (GI) symptoms are common among breast cancer patients undergoing chemotherapy, negatively impacting treatment outcomes and quality of life. Evidence points to inflammatory processes as the underlying cause of chemotherapy-associated GI symptoms. Relatedly, omega-3 (n-3) has been linked to anti-inflammatory processes. The primary objective of this study was to examine the associations between baseline n-3, baseline inflammatory markers and GI symptom progression in early-stage breast cancer patients receiving chemotherapy.

METHODS

In this secondary analysis of a prospective cohort study, we analyzed baseline levels of inflammatory biomarkers (measured using a Luminex bead-immunoassay) and plasma levels of DHA, EPA, and FFA (measured using enzyme-linked immunosorbent assay). GI symptoms were assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire in Cancer Patients (EORTC QLQ-C30) symptom scale scores at baseline (T1) and at least 6 weeks after, during chemotherapy (T2). Inferential statistics were used to analyze associations between the variables of interest.

RESULTS

The analysis included 31 female breast cancer patients (mean age ± SD = 50.5 ± 8.8; 89.6% receiving anthracycline-based chemotherapy). Higher levels of docosahexaenoic acid (DHA) and interleukin-8 (IL-8) predicted increases in appetite loss. Similarly, higher IL-8 predicted worsened nausea and vomiting.

CONCLUSION

Baseline IL-8 and DHA predicted GI symptom progression in early-stage breast cancer patients undergoing chemotherapy. Future studies are required to evaluate how therapeutic intervention targeting these biomarkers may mitigate gastrointestinal symptoms in cancer patients.

Brain-derived neurotrophic factor as a biomarker in cancer-related cognitive impairment among adolescent and young adult cancer patients

Brain-derived neurotrophic factor (BDNF) improves cognitive function by stimulating neurogenesis and neuroplasticity. We hypothesize that higher plasma BDNF levels are protective against cognitive toxicity among adolescent and young adult cancer patients (15-39 years old). In a prospective, longitudinal study, we recruited 74 newly diagnosed cancer and 118 age-matched non-cancer controls who completed the Cambridge Neuropsychological Test Automated Battery (CANTAB), Functional Assessment of Cancer Therapy-Cognitive Function questionnaire (FACT-Cog) and blood draws. Plasma BDNF was quantified using an enzyme-linked immunosorbent assay. Genomic DNA from buffy coat was genotyped for BDNF Val66Met. Most cancer participants were diagnosed with breast (24%) and head/neck (22%) cancers. After adjusting for sociodemographic variables (age, gender, race, marital status, education years), cancer participants had lower BDNF levels (ng/mL) at baseline (median: 10.7 vs 21.6, p < 0.001) and 6-months post-baseline (median: 8.2 vs 15.3, p = 0.001) compared to non-cancer controls. Through linear mixed modelling adjusted for sociodemographic variables, baseline cognition, fatigue, psychological distress, and time, we observed that among cancer participants, lower baseline BDNF levels were associated with worse attention (p = 0.029), memory (p = 0.018) and self-perceived cognitive abilities (p = 0.020) during cancer treatment. Met/Met was associated with enhanced executive function compared to Val/Val (p = 0.012). Plasma BDNF may serve as a predictive biomarker of cancer-related cognitive impairment.

Cognitive impairment in adolescent and young adult cancer patients: Pre-treatment findings of a longitudinal study

BACKGROUND

There is little information about cancer-related cognitive impairment (CRCI) in adolescent and young adults (AYA, 15-39 years old) due to its rare incidence. Here, we present the pre-treatment (before chemotherapy or radiotherapy) evaluation of cognitive function and ability of AYA with cancer (AYAC) in a multicentered cohort study.

METHODS

Newly diagnosed AYAC and age-matched healthy controls (HC) were recruited between 2018 and 2021. The primary outcome was the comparison of pre-treatment cognitive impairment defined as 2 standard deviations (SDs) below the HC on ≥1 cognitive test, or >1.5 SDs below on ≥2 tests using CANTAB® between AYAC and HC. Secondary outcomes included self-perceived cognitive ability assessed by FACT-Cog v3 and biomarkers (inflammatory cytokines and brain-derived neurotrophic factor [BDNF]).

RESULTS

We recruited 74 AYAC (median age = 34) and 118 HC (median age = 32). On objective cognitive testing, we observed three times more AYAC patients performed poorly on at least 2 cognitive tests compared to HC (40.5% vs. 13.6%, p < 0.001). AYAC self-perceived less degree of cognitive impairment than HC (p < 0.001). However, AYAC perceived a greater impact of cognitive changes on their quality of life compared to HC (p = 0.039). Elevated baseline inflammatory markers (IL-2, IL-4, IL-6, IL-8, IL-10 and IFN-γ) were observed among AYAC compared to HC, and baseline BDNF was lower in AYAC compared to HC. Interaction effects between cancer diagnosis and biomarkers were observed in predicting cognitive function.

CONCLUSION

With the pre-existence of CRCI and risk factors of neuroinflammation even prior to systemic therapy, AYAC should receive early rehabilitation to prevent further deterioration of cognitive function after initiation of systemic therapies. (ClinicalTrials.gov Identifier: NCT03476070).

Tissue-based next generation sequencing (NGS) testing in solid tumors: A single-center experience in Malaysia

e15121

Background: There is an increased appreciation for precision oncology in which clinicians are utilizing NGS testing to guide treatment selection and to identify resistance mutations. This study aims to identify clinically significant biomarkers in prospectively collected FFPE tumor tissue specimens. Genomic testing of molecular alterations was conducted using an in-house 50-gene hotspot APEX panel (MiRXES). Herein, we report a single center experience with targeted NGS panel testing in solid tumors. Methods: The analyzed cohort consisted of 75 clinical samples submitted for molecular testing over a 3-month period from Beacon Hospital, Malaysia (October to December 2021). The identified variants were tiered according to AMP/ASCO/CAP guidelines, in which actionable targets are defined as being able to be matched with existing FDA-approved drugs, including off-label prescriptions. Results: Among the samples received, 85.3% of samples passed quality control requirements for SNV/Indels and amplifications. Majority of the tumor types were categorized under colorectal cancer (20.3%), NSCLC (18.7%), followed by breast cancer (13.6%). Of the samples successfully sequenced, actionable targets were identified in 76.2% of patients, with Tier I variants [such as EGFR exon19del (6), EGFR exon20insertion (1), ERBB2 amp (5), KRAS G12C (3), KRAS G12D (1), KRAS G12V(1), KRAS G12F (1) KRAS G13D (1), PIK3CA H1047R (1), MET exon 14 skipping (1) and NRAS Q61H (1)) being identified in 20 patients. When stratified across tumor types, actionability rates were found to differ, with 100.0%, 83.3% and 81.8%, of tested tissues samples yielding results informing treatment selection or resistance mutations for breast, colorectal and NSCLC respectively. Based on APEX-tissue testing, the median number of actionable genes identified was 2 (IQR: 0 – 3) while the mean time from sampling to report was 4.7 days. Conclusions: This study shows the clinical utility and feasibility of targeted panel testing in cancer types of breast, colorectal and NSCLC. With fast turnaround time of 4 working days, this ensures timely access to treatment for patients.

A risk classification model for prioritising the management of quality issues relating to substandard medicines in Singapore

BACKGROUND

Monitoring for substandard medicines by regulatory agencies is a key post-market surveillance activity. It is important to prioritise critical product defects for review to ensure that prompt risk mitigation actions are taken.

METHODS

A regulatory risk impact prioritisation model for product defects (RISMED) with 11 factors considering the seriousness and extent of impact of a defect was developed. The model generated an overall score that categorised cases into high, medium or low impact. The model was further developed into a statistical risk scoring model (stat-RISMED) using multivariate logistic regression that classified cases into high and non-high impact. Both models were evaluated against an expert-derived gold standard annotation corpus and tested on an independent dataset.

RESULTS

Product defect cases received from January 2011 to June 2020 (n = 660) were used to train stat-RISMED and cases from July 2020 to June 2021 (n = 220) for validation. The stat-RISMED identified four factors associated with high impact cases, namely defect classification based on MedDRA-HSA terms, therapeutic indication of product, detectability of defect and whether any overseas regulatory actions were performed. Compared to RISMED, stat-RISMED achieved an improved sensitivity (94% vs 42%) and positive predictive value (47% vs 43%) for the identification of high impact cases, against the gold standard labels.

CONCLUSIONS

This study reported characteristics that predicts cases with high impact, and the use of a statistical model to identify such cases. The model may potentially be applied to prioritise product defect issues and strengthen overall surveillance efforts of substandard medicines. This article is protected by copyright. All rights reserved.

Feasibility of Cognitive Training to Promote Recovery in Cancer-Related Cognitive Impairment in Adolescent and Young Adult Patients

Background: Computer-based cognitive rehabilitation programs may help adolescent and young adult (AYA) patients with cancer-related cognitive impairment. This pilot study investigated the feasibility of cognitive rehabilitation as a preventive intervention for AYA patients receiving chemotherapy. Explorative objectives included the correlation of cognitive performance with serum brain-derived neurotrophic factor (BDNF). Methods: This pilot prospective study included English-speaking patients 12-25 years of age with a fist diagnosis of cancer requiring chemotherapy. Participants enrolled in the intervention arm participated in a computer-based neurocognitive training program for 20-30 minutes daily for 16 weeks. Outcome measures, including engagement with and completion of computerized neurocognitive testing and serum BDNF levels, were obtained within the first month following diagnosis, ∼16 and 24 weeks from enrollment. Results: Fourteen of 18 eligible patients provided consent, with 7 patients assigned to each the intervention arm and nonintervention arm. Seventy-one percent of the patients in the intervention arm completed at least 80% of the required activities. Compared to baseline, patients in the nonintervention arm demonstrated higher prevalence of impairment in four of the six cognitive domains (processing speed, visual attention, attention/working memory, and executive function) at the end of the study period. There was a nonstatistically significant reduction of serum BDNF levels over time, which was observed in both intervention and nonintervention arms. Conclusion: This pilot study provides some evidence that it is feasible for AYAs with new cancer diagnoses to receive standardized cognitive rehabilitation. Patients receiving cognitive activities experienced less impairment in numerous cognitive domains.

Relationship between cytokines and brain-derived neurotrophic factor (BDNF) in trajectories of cancer-related cognitive impairment

Cytokines facilitate the peripheral immune and cerebral response, through their ability to modulate the expression of brain derived neurotrophic factor (BDNF). Cytokines and BDNF are implicated in cancer-related cognitive impairment (CRCI), but their relationship has not been clearly defined for this condition. The aim of this study was to evaluate the associations of cytokines and BDNF among early stage breast cancer (ESBC) patients with different CRCI trajectories. This was a multicenter longitudinal study involving 136 ESBC patients. CRCI was assessed using the FACT-Cog (V3) questionnaire. Plasma cytokines and BDNF levels were quantified at three time points throughout chemotherapy. The associations between cytokines and BDNF were analyzed using linear mixed models, with interaction terms for CRCI status. All cytokines analyzed showed inverse associations with BDNF levels. There was a significant interaction between IL-6 and the persistent impairment trajectory, which would impact on BDNF levels (p = 0.026). The inverse associations with BDNF were more pronounced for IFN-γ, IL-1β, IL-4, IL-8, and GM-CSF in patients with persistent CRCI. The coefficient values for IL-2, IL-4, and TNF-α also indicate that there was a greater magnitude of decrease in BDNF level for every unit of cytokine increase in patients with acute and persistent CRCI, compared to patients without CRCI. The differential associations between cytokines and BDNF may be indicative of probable susceptibility to the elevation of cytokines. Further research is required to elucidate the specific associations of cytokines and BDNF, along with their contributions to acute and persistent CRCI.

Cancer-related cognitive impairment in patients with non-central nervous system malignancies: an overview for oncology providers from the MASCC Neurological Complications Study Group

Cancer-related cognitive impairment (CRCI) is commonly experienced by individuals with non-central nervous system cancers throughout the disease and treatment trajectory. CRCI can have a substantial impact on the functional ability and quality of life of patients and their families. To mitigate the impact, oncology providers must know how to identify, assess, and educate patients and caregivers. The objective of this review is to provide oncology clinicians with an overview of CRCI in the context of adults with non-central nervous system cancers, with a particular focus on current approaches in its identification, assessment, and management.

A study protocol for HEalth-Related quality of life-intervention in survivors of Breast and other cancers experiencing cancer-related fatigue using TraditionAL Chinese Medicine: the HERBAL trial

BACKGROUND

Cancer-related fatigue (CRF) is a debilitating condition which commonly affects cancer survivors. The management of CRF remains a challenge due to the lack of effective pharmacological interventions. Traditional Chinese medicine (TCM) could be a potential therapeutic option for CRF. The modified Xiang Bei Yang Rong Tang (XBYRT) is a TCM herbal decoction, formulated to improve fatigue symptoms in cancer survivors. This clinical trial aims to evaluate the efficacy and safety of XBYRT in improving CRF and quality of life (QOL) of cancer survivors.

METHODS

This is a single centre, randomized, double-blind, placebo-controlled, parallel trial. Eighty cancer survivors will be recruited and randomized to receive the XBYRT or placebo decoction, in a ratio of 1:1. Participants will consume the XBYRT/placebo decoction daily for 8 weeks and undergo assessments at baseline and 4, 8 and 10 weeks after baseline. The participants will be assessed for patient-reported outcomes (PRO), blood biomarkers and adverse events at each time point. The primary outcome is the overall health and QOL status, at 8 weeks follow-up. The secondary outcomes are the effects of XBYRT on fatigue levels, cancer-related cognitive impairment and QOL, as assessed by PRO. The incidence of adverse events and the effects of the XBYRT decoction on blood biomarkers associated with CRF will also be evaluated.

DISCUSSION

Efficacy and safety outcomes from this trial will provide important clinical data to guide future large-scale randomized controlled trials, and the evaluation of the objective blood biomarkers can help to delineate the biological mechanisms of CRF.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT04104113 . Registered on 26 September 2019.

Association of mitochondrial DNA content and displacement loop region sequence variations with cancer-related fatigue in breast cancer survivors receiving chemotherapy

Cancer-related fatigue (CRF) is characterized by a lack of energy, and mitochondrial dysfunction is postulated to contribute to its etiology. This prospective cohort study assesses the self-reported fatigue levels of early-stage breast cancer patients using the validated Multi-Dimensional Fatigue Symptom Inventory-Short Form (MFSI-SF) and blood samples drawn at three time points: before treatment, approximately 6 weeks, and 12 weeks after the initiation of chemotherapy. The aim of this study is to evaluate mitochondrial measures with CRF, over the course of chemotherapy using mitochondrial DNA (mtDNA content) and displacement loop (D-loop) region sequence variations at nucleotide positions 303, 489 and 514. The relative mtDNA copy number was determined via real-time quantitative polymerase chain reaction and compared between study time points and D-loop sequence variants. The association of mtDNA content with MFSI-SF total and sub-domain scores was analyzed in a sample of 155 patients (mean age ± SD: 51.7 ± 8.8 years). The median mtDNA content decreased over 12 weeks after the initiation of chemotherapy (p < 0.001). Baseline mtDNA content was lower for nucleotide position 303 in sequence variations than for the reference sequence (67.2 copies vs 79.1 copies, p = 0.03). Physical fatigue negatively correlated with mtDNA content in both unadjusted (β = -0.0075, p = 0.048) and adjusted models (β = -0.0062, p = 0.042), accounting for age, anxiety, insomnia, haemoglobin levels and body mass index. Our findings add to the literature indicating that mitochondrial function serves as an important target for mitigating CRF.

Educational needs of oncology pharmacists: A survey by the International Society of Oncology Pharmacy Practitioners

BACKGROUND

The International Society of Oncology Pharmacy Practitioners (ISOPP) is committed to providing educational resources to members for their continuous learning and professional development. This survey was conducted to explore the educational needs of International Society of Oncology Pharmacy Practitioners members for the purpose of developing resources to support future learning relevant to the diverse global pharmacy practitioner membership of our society.

METHODS

A cross-sectional survey of International Society of Oncology Pharmacy Practitioners membership was conducted between 10 December 2018 and 15 January 2019. The survey contained 17 questions and consisted of four sections: (1) respondents' demographics, (2) common challenges/barriers faced by members in accessing oncology pharmacy education, (3) areas within oncology pharmacy where members need education and (4) preferred methods of education delivery. Descriptive statistics were utilized to summarize survey results.

RESULTS

The survey was completed by 62 out of 363 International Society of Oncology Pharmacy Practitioners members (17% response rate). Respondents were from 19 different countries, representing all the habitable continents. Most respondents were practicing in North America (21%), Oceania (21%) and Asia (16%). The majority of respondents worked in inpatient cancer units (60%), ambulatory tertiary cancer centres (31%) and academia (26%). Reported barriers to accessing education relevant to oncology pharmacy practice included lack of financial support (44%), time spent travelling to attend educational activities (39%), limited learning opportunities in their country of practice (34%) and limited growth of the oncology pharmacy discipline in their country of practice (32%). The content areas of greatest demand included pharmacotherapy of various cancers followed by oncology pharmacy research, International Society of Oncology Pharmacy Practitioners oncology pharmacy practice standards, supportive care and medication safety. Among educational activities offered by International Society of Oncology Pharmacy Practitioners, respondents valued annual International Society of Oncology Pharmacy Practitioners symposia and Journal of Oncology Pharmacy Practice the most. Most respondents (87%) indicated webinars as an effective educational tool.

CONCLUSION

Among an international oncology pharmacist cohort, we identified practice areas prioritized by pharmacists for continuing and professional development. Time and cost were common barriers to education, both in developing and developed countries. These survey findings may help to guide future education initiatives of International Society of Oncology Pharmacy Practitioners and other providers of pharmacist oncology education.

HPLC-MS/MS coupled with equilibrium dialysis method for quantification of free drug concentration of pazopanib in plasma

Background

The selective occurrence of hepatotoxicity observed with use of pazopanib may be attributed to its high level of plasma protein binding and low hepatic extraction ratio. The primary objective was to investigate changes in free drug concentration amongst patients with varying albumin concentrations.

Methods

A HPLC-MS/MS method using C18 column (4.6 × 150 mm, 5 μm) with ESI source in positive mode had been developed and validated for the quantitative determination of free pazaopanib concentration in human plasma. Prior to sample preparation, patient samples were subjected to 6-hour equilibrium dialysis with molecular weight cut-off set at 8000 Da.

Results

The calibration curves were linear over the range of 5–1000 ng/mL, with a lower limit of quantification of 5 ng/mL. The intra-day and inter-day precisions and accuracies were all within ± 15 %, at 3 different quality controls. Higher median fraction unbound of pazopanib were observed in patients (n = 17) with lower than normal albumin concentrations.

Conclusion

With the developed assay, monitoring of plasma free concentrations may be evaluated as an indicator of pazopanib exposure in patients.

Role of Exosomes in Cancer-Related Cognitive Impairment

A decline in cognitive function following cancer treatment is one of the most commonly reported post-treatment symptoms among patients with cancer and those in remission, and include memory, processing speed, and executive function. A clear understanding of cognitive impairment as a result of cancer and its therapy can be obtained by delineating structural and functional changes using brain imaging studies and neurocognitive assessments. There is also a need to determine the underlying mechanisms and pathways that impact the brain and affect cognitive functioning in cancer survivors. Exosomes are small cell-derived vesicles formed by the inward budding of multivesicular bodies, and are released into the extracellular environment via an exocytic pathway. Growing evidence suggests that exosomes contribute to various physiological and pathological conditions, including neurological processes such as synaptic plasticity, neuronal stress response, cell-to-cell communication, and neurogenesis. In this review, we summarize the relationship between exosomes and cancer-related cognitive impairment. Unraveling exosomes’ actions and effects on the microenvironment of the brain, which impacts cognitive functioning, is critical for the development of exosome-based therapeutics for cancer-related cognitive impairment.

Distinct cytokine profiles across trajectories of self-perceived cognitive impairment among early-stage breast cancer survivors

The aim of the current study is to identify distinct cytokine profiles in relation to self-perceived cognitive trajectories. In our study cohort (n = 128), early-stage breast cancer patients were categorized into no impairment reported, acute, delayed, persistent and intermittent cognitive decline respectively. Pro-inflammatory cytokines were elevated compared to baseline; with TNF-α implicated in the acute cognitive trajectory while IL-6 and IL-8 were involved in the persistent cognitive trajectory. Our findings help to further our understanding of cytokine profiles implicated in cancer-related cognitive impairment (CRCI) and support the use of cytokine levels as biomarkers of cognitive decline over time.

Association of plasma leptin, pro-inflammatory adipokines and cancer-related fatigue in early-stage breast cancer patients: A prospective cohort study

Cancer‐related fatigue (CRF) is subjective and has wide inter‐individual variability. Given that leptin is commonly associated with fatigue syndrome, its use as a potential biomarker for CRF is being investigated. The primary objective of this study was to evaluate the association between leptin and CRF in early‐stage breast cancer patients receiving chemotherapy. In a prospective cohort study, patients completed assessments at baseline (T1), during chemotherapy (T2) and after chemotherapy (T3). Levels of plasma leptin and adipokines were measured using a Luminex bead‐immunoassay and CRF was measured using the Multi‐Dimensional Fatigue Symptom Inventory‐Short Form (MFSI‐SF). Data were analysed longitudinally using a generalised estimating equation incorporating clinically relevant parameters and pro‐inflammatory adipokines. The analysis included 136 patients (mean age ± SD = 51.5 ± 8.8 years; 69.1% receiving anthracycline‐based chemotherapy). More patients experienced CRF at T3 (23.8%) than at T2 (13.8%) compared to baseline. An increase was observed in the median plasma leptin level at T2, followed by a decrease at T3 (T1: 4.07 ng/mL, T2: 4.95 ng/mL and T3: 3.96 ng/mL). In the multivariate model, the change in leptin levels over time was significantly associated with the total MFSI‐SF score (β = −0.15, P = 0.003) after adjusting for the tumour necrosis factor‐α (TNF‐α) level, anxiety, depression, insomnia, age, menopausal status and type of chemotherapy. This is the first study to report leptin as a biomarker that predicts the onset of CRF over time. Future studies are required to validate the findings.

Prechemotherapy Levels of Plasma Dehydroepiandrosterone and Its Sulfated Form as Predictors of Cancer-Related Cognitive Impairment in Patients with Breast Cancer Receiving Chemotherapy

Study Objective

Dehydroepiandrosterone (DHEA) and its sulfated form (DHEAS)—jointly referred to as DHEA(S)—are neurosteroids known to regulate brain development and function that have been found to be positively correlated with cognitive function. It is unknown whether prechemotherapy plasma DHEA(S) levels are associated with the onset of cancer‐related cognitive impairment (CRCI). The objective of this study was to evaluate whether an association exists between prechemotherapy plasma DHEA(S) levels and onset of CRCI in patients with breast cancer receiving chemotherapy.

Design

Multicenter, prospective cohort study.

Setting

Two specialized cancer centers in Singapore.

Patients

Eighty‐one patients with early‐stage breast cancer (stages I–III) who had no prior exposure to chemotherapy and/or radiotherapy and were scheduled to receive anthracycline‐based or taxane‐based chemotherapy treatment with curative intent.

Measurements and Main Results

Patients completed assessments for self‐perceived and objective cognitive function at three time points: prechemotherapy (T1), during chemotherapy (T2), and after chemotherapy (T3). Plasma samples were collected prior to chemotherapy, and DHEA(S) levels were quantified by using ultra–high‐performance liquid chromatography–tandem mass spectrometry. Multivariable logistic regression was used to adjust for clinically important factors and to evaluate the association between prechemotherapy plasma DHEA(S) levels and CRCI. Mean ± SD age was 48.9 ± 9.3 years, with 27.8% of patients experiencing clinically significant cognitive impairment based on global Functional Assessment of Cancer Therapy–Cognitive Function scores. The mean ± SD prechemotherapy plasma DHEAS and DHEA levels were 1.61 ± 0.91 μmol/L and 19.21 ± 13.13 nmol/L, respectively. Prechemotherapy DHEAS levels were found to be associated with impairment in the self‐perceived cognitive domains of verbal fluency (adjusted odds ratio [OR] 0.27, 95% confidence interval [CI] 0.08–0.96) and mental acuity (adjusted OR 0.25, 95% CI 0.08–0.74). Conversely, DHEA levels were not associated with impairment in any cognitive subdomains.

Conclusion

Our findings suggest that patients with higher prechemotherapy DHEAS levels had lower odds of developing self‐perceived cognitive impairment. Future studies are required to further investigate the effect of DHEA(S) on specific cognitive domains and to validate our findings in independent cohorts.

Replication and Meta-analysis of the Association between BDNF Val66Met Polymorphism and Cognitive Impairment in Patients Receiving Chemotherapy

Cancer-related cognitive impairment (CRCI) adversely affects cancer patients. We had previously demonstrated that the BDNF Val66Met genetic polymorphism is associated with lower odds of subjective CRCI in the multitasking and verbal ability domains among breast cancer patients receiving chemotherapy. To further assess our previous findings, we evaluated the association of BDNF Val66Met polymorphism with subjective and objective CRCI in a temporally separate cohort of patients and pooled findings from both the original (n = 145) and current (n = 193) cohorts in a meta-analysis. Subjective CRCI was assessed using FACT-Cog. Objective CRCI was evaluated using computerized neuropsychological tests. Genotyping was carried out using Sanger sequencing. The association of BDNF Val66Met genotypes and CRCI was examined with logistic regression. A fixed-effect meta-analysis was conducted using the inverse variance method. In the meta-analysis (n = 338), significantly lower odds of CRCI were associated with Met allele carriers based on the global FACT-Cog score (OR = 0.52, 95% CI 0.29–0.94). Furthermore, Met allele carriers were at lower odds of developing impairment in the domains of memory (OR = 0.34, 95% CI: 0.17–0.70), multitasking (OR = 0.33, 95% CI: 0.18–0.59), and verbal ability (OR = 0.46, 95% CI: 0.24–0.88). Consistent with the previous study, lower odds of subjective CRCI among patients with the BDNF Met allele was observed after adjusting for potential confounders in the multitasking (OR = 0.30, 95% CI: 0.14–0.67) domain. In conclusion, carriers of the BDNF Met allele were protected against global subjective CRCI, particularly in the domains of memory, multitasking, and verbal ability. Our findings further contribute to the understanding of CRCI pathophysiology.

Impact of brain-derived neurotrophic factor genetic polymorphism on cognition: A systematic review

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) has an important role in the neurogenesis and neuroplasticity of the brain. This systematic review was designed to examine the association between BDNF Val66Met (rs6265) polymorphism and four cognitive domains-attention and concentration, executive function, verbal fluency, and memory, respectively.

METHODOLOGY

Primary literature search was performed using search engines such as PubMed and Scopus. Observational studies that evaluated the neurocognitive performances in relation to BDNF polymorphism within human subjects were included in this review, while animal studies, overlapping studies, and meta-analysis were excluded.

RESULTS

Forty of 82 reviewed studies (48.8%) reported an association between Val66Met polymorphism and neurocognitive domains. The proportion of the studies showing positive findings in cognitive performances between Val/Val homozygotes and Met carriers was comparable, at 30.5% and 18.3%, respectively. The highest percentage of positive association between Val66Met polymorphism and neurocognition was reported under the memory domain, with 26 of 63 studies (41.3%), followed by 18 of 47 studies (38.3%) under the executive function domain and four of 23 studies (17.4%) under the attention and concentration domain. There were no studies showing an association between Val66Met polymorphism and verbal fluency. In particular, Val/Val homozygotes performed better in tasks related to the memory domain, while Met carriers performed better in terms of executive function, in both healthy individuals and clinical populations.

CONCLUSION

While numerous studies report an association between Val66Met polymorphism and neurocognitive changes in executive function and memory domains, the effect of Met allele has not been clearly established.