Chemotherapy and Cognition: Effects, Potential Mechanisms, and Management

Thematic analysis of illness narratives as an example of an approach to better understand the lived experience of women diagnosed with breast cancer in Spain

OBJECTIVE

To explore the lived experience of women diagnosed with breast cancer through the analysis of illness narratives, as an example of a narrative-based medicine approach.

SETTING

Spain.

PARTICIPANTS

Nine narratives stemming from non-fiction books, and six from interviews through online platforms. All participants were cis women and their ages ranged between 34 and 60 years. The inclusion criteria were being a woman and having been diagnosed with and treated for breast cancer in Spain.

RESULTS

The main topics that appeared on the analysis were: secondary effects of treatment, breast loss and scars, breast reconstruction, long-term effect of treatment, positive attitude, illness as learning and use of language. Although the results of this research are preliminary, it can be said that societal expectations quickly became a burden for the patients. Moreover, there was no common behavioural pattern among the participants and how they chose to manage their cancer journey. Choosing whether or not to hide their baldness, go through reconstructive surgery or fulfil the 'patient role' were options they wanted to review based on their own priorities, and not because of external impositions. Even though the women agreed with the benefits of having a positive attitude, they also asked for space to feel rage and sadness, not to be compared with others and to be heard with no haste, as well as to be accompanied beyond the treatment, and for their long-term effects of medications to be validated. The importance of the type of comments and language used is emphasised.

CONCLUSION

A narrative-based medicine approach enables us to incorporate the patient experience into the understanding of breast cancer. We encourage clinicians to be aware of the concepts of normality held by women, and to welcome different choices and different ways to experience illness.

Common cancer treatments targeting DNA double strand breaks affect long-term memory and relate to immediate early gene expression in a sex-dependent manner

DNA double strand breaks (DSBs) have been highly studied in the context of cancers, as DSBs can lead to apoptosis or tumorigenesis. Several pharmaceuticals are widely used to target DSBs during cancer therapy. Amifostine (WR-2721) and etoposide are two commonly used drugs: amifostine reduces DSBs, whereas etoposide increases DSBs. Recently, a novel role for DSBs in immediate early gene expression, learning, and memory has been suggested. Neither amifostine nor etoposide have been assessed for their effects on learning and memory without confounding factors. Moreover, sex-dependent effects of these drugs have not been reported. We administered amifostine or etoposide to 3-4-month-old male and female C57Bl/6J mice before or after training in fear conditioning and assessed learning, memory, and immediate early genes. We observed sex-dependent baseline and drug-induced differences, with females expressing higher cFos and FosB levels than males. These were affected by both amifostine and etoposide. Post-training injections of amifostine affected long-term contextual fear memory; etoposide affected contextual and cued fear memory. These data support the hypothesis that DSBs contribute to learning and memory, and that these could play a part in cognitive side effects during common treatment regimens. The sex-dependent effects also highlight an important factor when considering treatment plans.

Neuroimmune reactivity marker expression in rodent models of chemotherapy-induced cognitive impairment: A systematic scoping review

BACKGROUND

Chemotherapy-induced cognitive impairment (CICI) is a debilitating side effect arising from chemotherapy treatments. The condition is characterised by a range of cognitive deficits including impairment to memory, attention, and concentration. Whilst the underlying mechanisms that contribute to CICI remain unclear, neuroinflammation has been suggested as one key contributor.

METHOD

A comprehensive systematic search of EMBASE and Medline via PubMed was conducted to identify studies on neuroimmune reactivity marker expression changes and resulting cognitive changes in preclinical rodent models of CICI.

RESULTS

A total of twenty studies met the eligibility criteria and were included in the scoping review. There was significant heterogeneity in the methodology employed in the included studies. Our findings demonstrate that widespread changes in cytokines, chemokines, microglia reactivity, and astrocyte reactivity are observed in CICI in the brain regions expected to be affected, given the nature of the cognitive impairment observed in CICI.

CONCLUSIONS

Although there was considerable heterogeneity in study design that made comparisons between studies difficult, our findings suggest that neuroinflammation commonly occurs in CICI preclinical rodent models and shows an association with cognitive impairment.

Systematic review of cognitive sequelae of non-central nervous system cancer and cancer therapy

PURPOSE

The aim of this review is to provide an updated overview of chemotherapy-related cognitive impairment (CRCI) in patients with cancer outside central nervous system (CNS), its incidence and prevalence, the cognitive pattern in neuropsychological studies, neuroimaging findings, and the relationship between chemobrain and aging. Methodological limitations of studies are also discussed.

METHODS

This review was guided by the PRISMA statement. The MEDLINE and Scopus databases were employed to search articles about CRCI in non-CNS cancer patients published from January 2004 to September 2019. Two types of research were reviewed: prospective studies addressing the effects of chemotherapy on cognition and systematic reviews about factors related with CRCI, also as neuroimaging findings and current available treatments.

RESULTS

Fifty-nine studies meeting the criteria were analyzed: 47 were longitudinal studies on cancer and cognition and 12 were reviews on risk factors, neuroimaging, and treatment. The majority of studies find cognitive impairment in patients with cancer treated with chemotherapy. The body of the literature on breast cancer is the most abundant, but there are also studies on colorectal, testicular, and lung cancer. Neuroimaging studies show changes in structure and activation in patients undergoing chemotherapy. Non-pharmacological treatment is effective for improving cognition and quality of life.

CONCLUSIONS

The occurrence of CRCI during the course of treatment in people with different types of cancer is frequent. Some risk factors have been identified, but CRCI is a complex phenomenon, with mediating factors related to cancer and treatment and moderating factors related with lifestyle and health.

IMPLICATIONS FOR CANCER SURVIVORS

This review highlights the importance of recognizing that this cognitive dysfunction is frequent, mild to moderate in nature but with great impact on quality of life.

Patient perceptions of a 1-h art-making experience during blood and marrow transplant treatment

Patients with various forms of cancer receiving blood and marrow transplant (BMT) treatment at an outpatient clinic develop chemotherapy-related symptoms and an increased desire to use complementary and alternative medicine in order to address these symptoms. Art-making offers an inexpensive way to pass time and relieve symptoms during long hours in treatment. Twenty-one BMT patients painted a tile and participated in research. Researchers used semi-structured interviews to understand patients' experiences with art-making. Interviews were recorded, transcribed and coded independently by researchers who met to agree on themes. Ten themes emerged from the data including, meaningful activity (32.2%), expression (18.7%), passing time (13.2%), BMT process (12.1%), social outlet (8.1%), therapy-related symptoms (7.3%), negative aspects of painting (5.9%) and encouragement to paint (2.6%). The results of this study revealed that art-making experience can provide patients a meaningful activity during treatment and an outlet to express their feelings.

Chemotherapy altered brain functional connectivity in women with breast cancer: a pilot study

Adjuvant chemotherapy is associated with improvements in long-term cancer survival. However, reports of cognitive impairment following treatment emphasize the importance of understanding the long-term effects of chemotherapy on brain functioning. Cognitive deficits found in chemotherapy patients suggest a change in brain functioning that affects specific cognitive domains such as attentional processing and executive functioning. This study examined the processes potentially underlying these changes in cognition by examining brain functional connectivity pre- and post-chemotherapy in women with breast cancer. Functional connectivity examines the temporal correlation between spatially remote brain regions in an effort to understand how brain networks support specific cognitive functions. Nine women diagnosed with breast cancer completed a functional magnetic resonance imaging (fMRI) session before chemotherapy, 1 month after, and 1 year after the completion of chemotherapy. Seed-based functional connectivity analyses were completed using seeds in the intraparietal sulcus (IPS) to examine connectivity in the dorsal anterior attention network and in the posterior cingulate cortex (PCC) to examine connectivity in the default mode network. Results showed decreased functional connectivity 1 month after chemotherapy that partially returned to baseline at 1 year in the dorsal attention network. Decreased connectivity was seen in the default mode network at 1 month and 1 year following chemotherapy. In addition, increased subjective memory complaints were noted at 1 month and 1 year post-chemotherapy. These findings suggest a detrimental effect of chemotherapy on brain functional connectivity that is potentially related to subjective cognitive assessment.

Memory and cancer: a review of the literature

The mental health of cancer survivors has not always been the primary emphasis of treatment protocols since physical health outcomes have taken precedence. Older cancer survivors experience a double jeopardy since they are at risk for memory impairments and mild cognitive impairment and because they are greater than 55 years of age. Of the 9.6 million cancer survivors in the US who have completed active treatment, many report cognitive difficulties, with labels such as "chemo brain," "not as sharp," "woolly-headedness," or the "mind does not work as quickly". To date, most of our knowledge of cognitive impairment in cancer survivors comes from female breast cancer survivors. Studies indicate that these survivors have diminished executive function, verbal memory, and motor function. Cancer survivors want to live independently in the community for as long as possible however, these cognitive deficits may prevent this desired lifestyle. To broaden our understanding this paper reviews the literature on the cognitive impairment and memory deficits experienced by three groups of cancer survivors breast, colorectal, and prostate cancer, that make up 60% of all survivors nationally. Even though mental health declined after a cancer diagnosis, the long-term outcomes of cancer survivors did not differ from persons without cancer in depression or cognitive function.

Tibetan sound meditation for cognitive dysfunction: results of a randomized controlled pilot trial

OBJECTIVE

Although chemotherapy-induced cognitive impairment is common among breast cancer patients, evidence for effective interventions addressing cognitive deficits is limited. This randomized controlled trial examined the feasibility and preliminary efficacy of a Tibetan Sound Meditation (TSM) program to improve cognitive function and quality of life in breast cancer patients.

METHODS

Forty-seven breast cancer patients (mean age 56.3 years), who were staged I-III at diagnosis, 6-60 months post-chemotherapy, and reported cognitive impairment at study entry were recruited. Participants were randomized to either two weekly TSM sessions for 6 weeks or a wait list control group. Neuropsychological assessments were completed at baseline and 1 month post-treatment. Self-report measures of cognitive function (Functional Assessment of Cancer Therapy (FACT)-Cog), quality of life (SF-36), depressive symptoms (Center for Epidemiologic Studies Depression Scale), sleep disturbance (Pittsburgh Sleep Quality Index), fatigue (Brief Fatigue Inventory), and spirituality (FACT-Sp) were completed at baseline, the end of treatment, and 1 month later.

RESULTS

Relative to the control group, women in the TSM group performed better on the verbal memory test (Rey Auditory Verbal Learning Test trial 1) (p = 0.06) and the short-term memory and processing speed task (Digit Symbol) (p = 0.09) and reported improved cognitive function (p = 0.06), cognitive abilities (p = 0.08), mental health (p = 0.04), and spirituality (p = 0.05) at the end of treatment but not 1 month later.

CONCLUSIONS

This randomized controlled trial revealed that TSM program appears to be a feasible and acceptable intervention and may be associated with short-term improvements in objective and subjective cognitive function as well as mental health and spirituality in breast cancer patients.

Evidence for acute neurotoxicity after chemotherapy

OBJECTIVE

Chronic neurotoxicity is a recognized long-term complication following chemotherapy in a range of diseases. Neurotoxicity adversely affects patients' quality of life. The objective of this study is to examine whether there is evidence of acute neurotoxicity.

METHODS

This prospective study included patients with secondary progressive multiple sclerosis (SPMS-BMT, n = 14) and hematological malignancies (HM-BMT, n = 17) receiving chemotherapy as preconditioning for bone marrow transplant. The control groups included SPMS patients matched for demographic and clinical data (SPMS-PL, n = 14) and healthy controls (n = 14). Neurodegeneration was assessed at baseline and longitudinally (months 1, 2, 3, 6, 9, 12, 24, and 36), combining a clinical scale for disability (Expanded Disability Status Scale [EDSS]), a serum protein biomarker for neurodegeneration (neurofilaments, NfH-SMI35), and brain atrophy measures (magnetic resonance imaging).

RESULTS

Disability progression was significantly more acute and severe following chemotherapy compared to placebo. Immediately after starting chemotherapy, serum NfH-SMI35 levels increased in 79% (p < 0.0001) of SPMS-BMT patients and 41% (p < 0.01) of HM-BMT patients compared to 0% of SPMS-PL patients or healthy controls. In SPMS-BMT serum NfH-SMI35 levels were > 100-fold higher 1 month after chemotherapy (29.73ng/ml) compared to baseline (0.28ng/ml, p < 0.0001). High serum NfH-SMI35 levels persisting for at least 3 months were associated with sustained disability progression on the EDSS (p < 0.05). Brain atrophy rates increased acutely in SPMS-BMT (-2.09) compared to SPMS-PL (-1.18, p < 0.05).

INTERPRETATION

Neurotoxicity is an unwanted acute side effect of aggressive chemotherapy.

Cognitive effects of androgen deprivation therapy in an older cohort of men with prostate cancer

OBJECTIVE

To determine the baseline prevalence of cognitive impairment in older men treated with ADT and to assess changes in cognitive performance over time.

METHODS AND RESULTS

Thirty-two patients (median age of 71 years, range 51-87) were administrated an extensive neuropsychological testing battery prior to ADT initiation, with 21 (65%) completing post-treatment evaluations 6 months later. At baseline, 45% scored >1.5 standard deviations below the mean on > or = 2 neuropsychological measures. Using standardized inferential statistics, no change in cognition was documented following treatment. The Reliable Change Index revealed that, on a case-by-case basis, 38% demonstrated a decline in measures of executive functioning and 48% showed improvement on measures of visuospatial abilities. Within exploratory analyses, patients who scored below expectation at baseline displayed no change in cognition, while patients with average or better scores at baseline displayed improvements in visuospatial planning and timed tests of phonemic fluency.

CONCLUSIONS

We found a high prevalence of lower than expected cognitive performance among a sample of patients just starting ADT for prostate cancer. Assessment of baseline cognitive function should be taken into account for future research and to inform clinical management.

Putative mechanisms of cognitive dysfunction in chemotherapy-naïve diffuse large B-cell lymphoma: a case report and review of the literature

Cognitive impairment is now recognized as a frequent consequence of treatments for cancers localized outside the central nervous system (CNS). In contrast, little attention has been given to the potentially deleterious cognitive effects from non-CNS cancers themselves. The present case study proposes that cognitive deficits occur in a subset of treatment-naive patients with diffuse large B-cell lymphoma in whom no gross evidence of lymphoma-related CNS involvement is apparent. Evidence is presented from a case study and elaborate putative mechanisms centering on deleterious effects of B-cell-mediated inflammatory cytokine secretion on neurons. Moreover, this case study speculates that genetic variability involving apolipoprotein E or other factors may mediate cognitive variability among these patients.

Cognitive function after chemotherapy in adults with solid tumours

BACKGROUND

Evidence is emerging that some cancer survivors suffer cognitive impairment after chemotherapy; the cause is unknown.

METHODS

Here we review studies evaluating cognitive impairment in adult cancer survivors and discuss methodological challenges associated with this research. We evaluate evidence for cognitive impairment in cancer patients, the incidence of self-reported impairment, and identify potential mechanisms and confounders.

RESULTS

Most studies of cognitive function are cross-sectional and report impairment in 15-45% of subjects. Longitudinal studies suggest that some impairment is present prior to receiving chemotherapy, and that this worsens in some patients. The aetiology is unknown. A larger number of subjects self-report changes in cognitive function after chemotherapy; this does not correlate with objective testing.

CONCLUSIONS

Cognitive impairment occurs in a subset of cancer survivors and is generally subtle. Most evidence suggests an association with chemotherapy although other factors associated with the diagnosis and treatment of cancer may contribute.