A meta-analysis of the neuropsychological effects of adjuvant chemotherapy treatment in women treated for breast cancer

Neuropsychological functioning in postmenopausal breast cancer patients treated with tamoxifen or exemestane after AC-chemotherapy: cross-sectional findings from the neuropsychological TEAM-side study

BACKGROUND

Previous studies have indicated that a subset of cancer patients treated with chemotherapy show cognitive deficits and/or experience cognitive complaints, whereas literature about the influence of hormonal therapies on cognition is sparse. Because of the accumulating knowledge about the importance of estrogen for cognitive functioning, there is growing concern about adjuvant hormonal therapy for breast cancer (BC) affecting cognition. We examined the cognitive functioning of postmenopausal BC patients who were, following doxorubicin/cyclophosphamide (AC) chemotherapy, randomized to tamoxifen or exemestane, and compared their performance with that of non-cancer controls.

MATERIALS AND METHODS

Thirty BC patients using tamoxifen and 50 patients using exemestane underwent interviews, questionnaires and cognitive tests, on average two years after completion of AC chemotherapy. Forty eight healthy controls were tested with similar measures.

RESULTS

Memory complaints were reported by 28% of AC/tamoxifen users, 24% of AC/exemestane users and 6% of healthy controls (p=0.02). Cognitive testing revealed no statistically significant differences between tamoxifen and exemestane users, but suggested that tamoxifen use is possibly related to worse verbal functioning, while exemestane use is possibly related to slower manual motor speed. Both patient groups performed significantly worse than healthy controls on verbal fluency and information processing speed.

DISCUSSION

Our findings show that sequential treatment of AC-chemotherapy and hormonal therapy in postmenopausal, primary BC is associated with lower test scores for certain cognitive functions, and provide indications for possibly distinctive associations for different types of hormonal treatment. Future research with larger groups is recommended to obtain a more definite picture.

Cognitive Effects of Systemic Therapy in Patients with Breast Cancer

Many patients with breast cancer complain about concentration and memory problems in connection with systemic therapy. A number of studies investigating the possible decrease in cognitive abilities were published in the 1980s. Numerous studies showed impaired performance of patients receiving chemotherapy. The results concerning profile, extent, and duration of cognitive impairments are, however, non-uniform. Increasing interest has been focused in the last years on effects of endocrine therapy on cognitive capacity - especially concerning the effects of the almost complete estrogen depletion caused by aromatase inhibitors. Often, the published studies did not evaluate particular effects of endocrine therapy without considering interference of cytotoxic treatment. Furthermore, the different endocrine medications (antiestrogens vs. aromatase inhibitors) were usually not regarded separately despite different mechanisms of action. Hence, the results of past investigations are also controversial. In the future, prospective trials with larger samples are necessary. Differentiation between chemotherapy and endocrine therapy is essential. Likewise, different types of endocrine therapy should be examined separately.

Cognitive function in breast cancer survivors compared to healthy age- and education-matched women

The cognitive function of breast cancer survivors (BC, n = 52) and individually matched healthy controls (n = 52) was compared on a battery of sensitive neuropsychological tests. The BC group endorsed significantly higher levels of subjective memory loss and scored significantly worse than controls on learning and delayed recall indices from the Rey Auditory Verbal Learning Test (AVLT). Defining clinically significant impairment as scores at or below the 7th percentile of the control group, the rate of cognitive impairment in the BC sample was 17% for total learning on the AVLT, 17% for delayed recall on the AVLT, and 25% for either measure. Findings indicate that a sizeable percentage of breast cancer survivors have clinically significant cognitive impairment.

Preliminary results of a longitudinal study of changes in cognitive function in breast cancer patients undergoing chemotherapy with doxorubicin and cyclophosphamide

OBJECTIVES

Recent studies suggest that standard dose chemotherapy for breast cancer may cross the blood-brain barrier. However, the evidence for chemotherapy-induced cognitive impairments in breast cancer patients is inconsistent. The purposes of this study in a sample of newly diagnosed patients with breast cancer were to (1) evaluate cognitive function prior to the administration of chemotherapy; (2) assess changes in cognitive function over time; and (3) evaluate potential relationships between cognitive function and anxiety, depression, fatigue, hemoglobin level, menopausal status, and perception of cognitive function.

METHODS

Thirty women with breast cancer completed neuropsychological testing before the initiation of chemotherapy and after four cycles of doxorubicin and cyclophosphamide. Descriptive statistics were used to summarize sample characteristics, and paired t-tests were carried out to evaluate for changes in neuropsychological test scores prior to and following completion of chemotherapy. Linear mixed model analyses were used to determine whether significant changes in neuropsychological test scores remained after controlling for anxiety, depression, fatigue, hemoglobin level, menopausal status, and perceived cognitive function.

RESULTS

Significant decreases in visuospatial skill (p<0.001) and total cognitive scores (p=0.001) were found following chemotherapy. In addition, a significant improvement was found in executive function (p=0.014). Of note, these changes remained significant even after controlling for anxiety, depression, fatigue, hemoglobin level, menopausal status, and perceived cognitive function.

CONCLUSIONS

Data from this study supported the hypothesis that chemotherapy may have a negative impact on select domains of cognitive function.

A framework for assessment in oncology rehabilitation

Although the incidence of cancer in the United States is high, improvements in early diagnosis and treatment have significantly increased survival rates in recent years. Many survivors of cancer experience lasting, adverse effects caused by either their disease or its treatment. Physical therapy interventions, both established and new, often can reverse or ameliorate the impairments (body function and structure) found in these patients, improving their ability to carry out daily tasks and actions (activity) and to participate in life situations (participation). Measuring the efficacy of physical therapy interventions in each of these dimensions is challenging but essential for developing and delivering optimal care for these patients. This article describes the acute and long-term effects of cancer and its treatment and the use of the World Health Organization's International Classification of Functioning, Disability and Health (ICF) as a basis for selection of assessment or outcome tools and diagnostic or screening tools in this population.

Adjuvant chemotherapy for breast cancer: effects on cerebral white matter seen in diffusion tensor imaging

PURPOSE

The purpose of this study was to examine the effect of adjuvant chemotherapy on normal-appearing white matter in women with breast cancer.

PATIENTS AND METHODS

Ten patients with early-stage breast cancer who were treated with adjuvant chemotherapy and 9 age-, education-, and IQ-matched healthy controls were studied with magnetic resonance imaging. Diffusion tensor imaging was used to calculate fractional anisotropy (FA), a measure of white matter integrity. Measurements were made in the genu and splenium of the corpus callosum. Participants also completed measures of processing speed, depression, and anxiety.

RESULTS

Relative to controls, patients had slower processing speed and lower FA in the genu. Processing speed was positively correlated with FA in the genu.

CONCLUSION

The results of this pilot study suggest that adjuvant chemotherapy affects normal-appearing white matter in the genu of the corpus callosum and that this is related to the cognitive deficits experienced by patients.

Factors affecting cancer survivors' employment and work ability

PURPOSE

Due to the improved prognosis of many forms of cancer, an increasing number of cancer survivors are both willing and able to return to work after their treatment. This has increased interest in studying work and cancer-related issues. The purpose of this paper is to give an overview of research on the impact of cancer on employment and work ability, on the effect of psychosocial factors on survivors' well-being, and to indicate research needs for the future.

RESULTS

Studies have shown that the majority of cancer survivors are able to continue working. There is, however, a group of cancer survivors who suffer from impaired health as a result of their illness, and this impairment sometimes leads to a decreased ability to work, or even disability. Employment and impaired work ability has most commonly been found to be associated with cancer type, type of treatment, health status, education and physical workload. The few studies that have focused on the effects of psychosocial factors in work life suggest that social support from occupational health services, and workplace accommodations for illness affect cancer survivors' return to work.

CONCLUSIONS

More research is needed on the impact of social factors at work, which seem to play an important role in cancer survivors' ability to continue working.

Behavioral symptoms in patients with breast cancer and survivors

Behavioral symptoms are a common adverse effect of breast cancer diagnosis and treatment and include disturbances in energy, sleep, mood, and cognition. These symptoms cause serious disruption in patients' quality of life and may persist for years after treatment. Patients need accurate information about the occurrence of these adverse effects as well as assistance with symptom management. This review considers four of the most common behavioral sequelae of breast cancer, namely fatigue, sleep disturbance, depression, and cognitive impairment. Research on the prevalence, mechanisms, and treatment of each symptom is described, concluding with recommendations for future studies.

The cognitive effects of adjuvant chemotherapy in early stage breast cancer: a prospective study

PURPOSE

The primary purpose of this study was to evaluate the cognitive effects of adjuvant chemotherapy in post-menopausal breast cancer patients.

PATIENTS AND METHODS

Breast cancer patients scheduled to receive adjuvant chemotherapy (n = 61) completed comprehensive cognitive testing before and after treatment. A control group of women receiving adjuvant hormonal therapy (n = 51) was tested at comparable intervals.

RESULTS

Mean scores for both patient groups were within the normal range relative to published norms on all cognitive tests at both time points, and generally inclined or stayed the same from baseline to retest in both groups. However, in an analysis of individual change scores, the chemotherapy patients were 3.3 times more likely than the hormonal patients to show reliable cognitive decline (31 and 12%, respectively). Chemotherapy subjects showing decline were less educated and had higher baseline depression scores than their counterparts who did not decline. Working memory was the cognitive domain most vulnerable to the effects of chemotherapy.

CONCLUSION

These data support previous findings of a subtle negative influence of chemotherapy on cognitive function in a subgroup of breast cancer patients. The results are discussed in terms of the importance of study design.

Quality of life and quality-adjusted survival (Q-TWiST) in patients receiving dose-intensive or standard dose chemotherapy for high-risk primary breast cancer

Quality of life (QL) is an important consideration when comparing adjuvant therapies for early breast cancer, especially if they differ substantially in toxicity. We evaluated QL and Q-TWiST among patients randomised to adjuvant dose-intensive epirubicin and cyclophosphamide administered with filgrastim and progenitor cell support (DI-EC) or standard-dose anthracycline-based chemotherapy (SD-CT). We estimated the duration of chemotherapy toxicity (TOX), time without disease symptoms and toxicity (TWiST), and time following relapse (REL). Patients scored QL indicators. Mean durations for the three transition times were weighted with patient reported utilities to obtain mean Q-TWiST. Patients receiving DI-EC reported worse QL during TOX, especially treatment burden (month 3: P<0.01), but a faster recovery 3 months following chemotherapy than patients receiving SD-CT, for example, less coping effort (P<0.01). Average Q-TWiST was 1.8 months longer for patients receiving DI-EC (95% CI, -2.5 to 6.1). Q-TWiST favoured DI-EC for most values of utilities attached to TOX and REL. Despite greater initial toxicity, quality-adjusted survival was similar or better with dose-intensive treatment as compared to standard treatment. Thus, QL considerations should not be prohibitive if future intensive therapies show superior efficacy.

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.

Cancer and cancer-therapy related cognitive dysfunction: an international perspective from the Venice cognitive workshop

A subset of survivors has cognitive impairment after cancer treatment. This is generally subtle, but may be sustained. In October 2006, the second international cognitive workshop was held in Venice. The workshop included neuropsychologists, clinical and experimental psychologists, medical oncologists, imaging experts, and patient advocates. The main developments since the first Cognitive Workshop in 2003 have been the following. (i) studies evaluating cognitive function in patients receiving chemotherapy for cancers other than breast cancer, and in patients receiving hormonal therapy for cancer. (ii) The publication of longitudinal prospective studies which have shown that some patients already exhibit cognitive impairment on neuropsychological testing before receiving chemotherapy, and some patients have deterioration in cognitive functioning from pre- to postchemotherapy. (iii) Studies of the underlying mechanisms of cognitive impairment both in patients and in animal models. (iv) Use of structural and functional imaging techniques to study changes in brain morphology and activation patterns associated with chemotherapy. (v) At present cognitive research in cancer is limited by methodological challenges and the lack of standardization in neuropsychological studies. The current workshop addressed many of these issues and established an international task force to provide guidelines for future research and information on how best to manage these symptoms.

A meta-analysis of the sensitivity of various neuropsychological tests used to detect chemotherapy-induced cognitive impairment in patients with breast cancer

PURPOSE/OBJECTIVES

To identify which neuropsychological tests have been used to evaluate chemotherapy-induced impairment in various domains of cognitive function in patients with breast cancer and to determine the sensitivity of each of the tests through estimation of effect size.

DATA SOURCES

Original studies published from 1966-June 2006.

DATA SYNTHESIS

Although an array of neuropsychological tests are available to measure the various domains of cognitive function, information is lacking regarding the sensitivity and specificity of the tests to detect changes in cognitive function from chemotherapy.

CONCLUSIONS

This meta-analysis provides initial data on the sensitivity of some neuropsychological tests to determine chemotherapy-induced changes in cognitive function in patients with breast cancer.

IMPLICATIONS FOR NURSING

The identification of sensitive neuro-psychological tests is crucial to further understanding of chemotherapy-induced cognitive impairments.

The Indiana University telephone-based assessment of neuropsychological status: a new method for large scale neuropsychological assessment

Sensitive measures of neuropsychological function were adapted to a telephone administration format for use in a large survey of quality of life in breast cancer survivors (BCS). Healthy controls (HC) and BCS were recruited from the community and administered the same neuropsychological test battery on two occasions separated by 1 week. Subjects were randomly assigned to conditions, stratified by diagnosis: In-person at Time-1 and In-person at Time-2 (P-P); Telephone at Time-1 and Telephone at Time-2 (T-T); T-P; and P-T. Four cognitive (Rey Auditory Verbal Learning Test, Controlled Oral Word Association, Digit Span, Symbol Digit) and two self-report measures (Squire Memory Self-Report Scale, Center for Epidemiological Studies Depression Scale) were used. The 106 subjects were randomized (54 HC and 52 BCS). Test-retest reliabilities (intraclass correlations) did not differ significantly by condition across the cognitive or self-report measures and ranged from moderate to near perfect (r's .43-.93; p's<.05). Mean scores at Time-1, practice effects (Time-1 to Time-2), and standard errors of measurement were comparable between In-person and Telephone administration formats. Results suggest that memory, attention, information processing speed, verbal fluency, and self-report of mood and memory can be measured reliably and precisely over the telephone.