The impact of adjuvant therapy for breast cancer on cognitive function: current evidence and directions for research

Impact of Cognitive Impairment in Patients with Gliomas

OBJECTIVES

To address the estimated rates of incidence, potential underlying etiologies, and cognitive domains affected from diagnosis and treatment. To describe potential cognitive function interventions.

DATA SOURCES

PubMed.

CONCLUSION

Adults with gliomas report that the most distressing, persistent, and greatest negative impact on their lives relates to the cognitive impairment they experience. However, there are several potential interventions that may prevent cognitive decline during treatment or maintain cognitive function long term.

IMPLICATIONS FOR NURSING PRACTICE

Awareness of cognitive sequela that adults with gliomas face can lead to early identification, full neurocognitive profiling, and implementation of evidence-based interventions for those experiencing cognitive impairments following cancer treatment.

Abnormal Development of Dendrites in Adult-Born Rat Hippocampal Granule Cells Induced by Cyclophosphamide

Although development of cognitive decline in cancer patients who receive chemotherapy is common, the underlying mechanism(s) remains to be identified. As abnormalities in adult hippocampal neurogenesis may serve as substrate for cognitive dysfunction, the present study examines the effect of cyclophosphamide (CPP), a widely prescribed chemotherapeutic agent, on dendritic development of adult-born hippocampal granule cells in the rat. CPP was intraperitoneally injected into male Sprague-Dawley rats once a week for four consecutive weeks. Four weeks and 1 week after the last dose of CPP, Morris water maze test and doublecortin (DCX) immunohistochemistry were carried out to determine the effects of CPP on cognitive function and the rate of hippocampal neurogenesis, respectively. Adult newborn hippocampal granule cells were labeled at the same day as the first dose of CPP and were examined 10 weeks after labeling. Results showed that cognitive decline induced by CPP was associated with both suppressed adult hippocampal neurogenesis and abnormal development of dendrites of newborn granule cells. The abnormalities of dendrites in newborn granule cells after CPP exposure included less dendritic branching, shorter total dendritic length, thinner and torturous dendritic shafts with intermittent appearances of varicosities, and lower spine densities of stubby and thin types along dendritic shafts, but an increased density of mushroom-like spines. Adult-born granule cells in the presence of CPP, a widely used anti-cancer medication, display abnormal dendritic morphologies and fewer dendritic spines which may underlie cognitive dysfunction.

Exercise for women receiving adjuvant therapy for breast cancer

BACKGROUND

A huge clinical research database on adjuvant cancer treatment has verified improvements in breast cancer outcomes such as recurrence and mortality rates. On the other hand, adjuvant and neoadjuvant therapy with chemotherapy and radiotherapy impacts on quality of life due to substantial short- and long-term side effects. A number of studies have evaluated the effect of exercise interventions on those side effects. This is an updated version of the original Cochrane review published in 2006. The original review identified some benefits of physical activity on physical fitness and the resulting capacity for performing activities of daily life. It also identified a lack of evidence for other outcomes, providing clear justification for an updated review.

OBJECTIVES

To assess the effect of aerobic or resistance exercise interventions during adjuvant treatment for breast cancer on treatment-related side effects such as physical deterioration, fatigue, diminished quality of life, depression, and cognitive dysfunction.

SEARCH METHODS

We carried out an updated search in the Cochrane Breast Cancer Group Specialised Register (30 March 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 2, 2015), MEDLINE (1966 to 30 March 2015), and EMBASE (1966 to 30 March 2015). We did not update the original searches in CINAHL (1982 to 2004), SPORTDiscus (1975 to 2004), PsycINFO (1872 to 2003), SIGLE (1880 to 2004), and ProQuest Digital Dissertations (1861 to 2004). We searched the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov for ongoing trials on 30 March 2015. We screened references in relevant reviews and published clinical trials.

SELECTION CRITERIA

We included randomised controlled trials that examined aerobic or resistance exercise or both in women undergoing adjuvant treatment for breast cancer. Published and unpublished trials were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed data extraction, assessed trials, and graded the methodological quality using Cochrane's 'Risk of bias' tool. Any disagreements were resolved through discussion or by consulting the third review author. We entered data into Review Manager for analysis. For outcomes assessed with a variety of instruments, we used the standardised mean difference (SMD) as a summary statistic for meta-analysis; for those assessed with the same instrument, we used the mean difference (MD).

MAIN RESULTS

For this 2015 update we included a total of 32 studies with 2626 randomised women, 8 studies from the original search and 24 studies from the updated search. We found evidence that physical exercise during adjuvant treatment for breast cancer probably improves physical fitness (SMD 0.42, 95% confidence interval (CI) 0.25 to 0.59; 15 studies; 1310 women; moderate-quality evidence) and slightly reduces fatigue (SMD -0.28, 95% CI -0.41 to -0.16; 19 studies; 1698 women; moderate-quality evidence). Exercise may lead to little or no improvement in health-related quality of life (MD 1.10, 95% CI -5.28 to 7.48; 1 study; 68 women; low-quality evidence), a slight improvement in cancer site-specific quality of life (MD 4.24, 95% CI -1.81 to 10.29; 4 studies; 262 women; low-quality evidence), and an improvement in cognitive function (MD -11.55, 95% CI -22.06 to -1.05; 2 studies; 213 women; low-quality evidence). Exercise probably leads to little or no difference in cancer-specific quality of life (SMD 0.12, 95% CI 0.00 to 0.25; 12 studies; 1012 women; moderate-quality evidence) and little or no difference in depression (SMD -0.15, 95% CI -0.30 to 0.01; 5 studies; 674 women; moderate-quality evidence). Evidence for other outcomes ranged from low to moderate quality. Seven trials reported a very small number of adverse events.

AUTHORS' CONCLUSIONS

Exercise during adjuvant treatment for breast cancer can be regarded as a supportive self care intervention that probably results in less fatigue, improved physical fitness, and little or no difference in cancer-specific quality of life and depression. Exercise may also slightly improve cancer site-specific quality of life and cognitive function, while it may result in little or no difference in health-related quality of life. This review is based on trials with a considerable degree of clinical heterogeneity regarding adjuvant cancer treatments and exercise interventions. Due to the difficulty of blinding exercise trials, all included trials were at high risk for performance bias. Furthermore, the majority of trials were at high risk for detection bias, largely due to most outcomes being self reported.The findings of the updated review have enabled us to make a more precise conclusion that both aerobic and resistance exercise can be regarded as beneficial for individuals with adjuvant therapy-related side effects. Further research is required to determine the optimal type, intensity, and timing of an exercise intervention. Furthermore, long-term evaluation is required due to possible long-term side effects of adjuvant treatment.

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

PURPOSE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Self-reported cognitive impairment in patients with cancer

PURPOSE

Cancer patients often report cognitive impairment, manifested as problems with concentration and memory, following cancer therapy. As part of a large multicenter survey of cancer patients undergoing treatment, we investigated the frequency and severity of self-reported problems with memory and concentration over time.

METHODS

A total of 595 patients undergoing treatment for solid tumors self-rated problems with memory and concentration, using an 11-point Likert scale (0 = "not present" to 10 = "as bad as you can imagine") at baseline before treatment began (T1), at their worst during treatment (T2), and at 6 months following treatment (T3). Any symptom level ≥ 7 was classified as "severe." Paired or independent t tests (as appropriate) with a Bonferroni correction were used to examine differences in symptoms over time and between patients treated with chemotherapy, radiation therapy, or both.

RESULTS

Concentration problems were reported by 48% of the 595 participants at T1 (5% severe), 67% at T2 (18% severe), and 58% (8% severe) at T3. Problems with memory were reported by 53% at T1 (4% severe), 67% (18% severe) at T2, and 68% (11% severe) at T3. The average frequency and severity of both symptoms in patients receiving chemotherapy, with or without radiation, increased significantly between T1 and T2 (P < .001). Both symptoms were less severe in patients receiving radiation alone at all three measurements than in either of the chemotherapy groups (all P values < .001). Symptoms at T3 were significantly higher than T1 for all groups (P < .001).

CONCLUSION

A significant proportion of patients undergoing cancer therapy self-report problems with memory and concentration. Cognitive problems get worse during treatment and are still in evidence 6 months following the conclusion of treatments.

Neuro-cognitive impairment in breast cancer patients: pharmacological considerations

Post-chemotherapy cognitive impairment has been an issue of concern in cancer survivors. While most reviews are focused on patient-related factors, it is proposed that drug-related factors may also be determinants. The objective of this review is to study the relationship between the types and dose intensities of chemotherapy regimens on cognitive impairment in breast cancer patients through a systematic literature search. Eighteen prospective studies were selected. The types, dose intensities and durations of chemotherapy regimens received by subjects were compared against prevalence results obtained in individual studies. It was observed that the duration of impairment varied across different generations of chemotherapy regimens. Concurrent administration of multiple cytotoxic agents can lead to a synergistic decline on cognition. Current clinical evidence is insufficient to evaluate the relationship between the types, dose intensities of chemotherapy regimens and cognitive impairment. More investigation is needed to examine the role of pharmacological factors in chemotherapy-associated cognitive changes.

Long-term cognitive impairment in older adult twins discordant for gynecologic cancer treatment

BACKGROUND

Research has found that patients treated for cancer generally have an increased risk for cognitive problems. However, many studies have focused on cognitive performance of cancer patients under the age of 65 who received chemotherapy treatment. Less studied is the extent to which cancer diagnosis may be associated with cognitive impairment as a late effect for older adults.

METHODS

In this retrospective, co-twin design study, twin pairs 65 years of age and older discordant for cancer were identified from the Swedish Twin Registry. A pair was included if both twins participated in cognitive screening, and the twin with the cancer history was screened at least 3 years after cancer diagnosis and treatment.

RESULTS

Female, but not male, survivors of cancer were significantly (odds ratio = 2.42, 95% confidence interval = 1.23-4.74) more likely to exhibit cognitive impairment 3 or more years after cancer diagnosis and treatment as their co-twin without a history of cancer. In particular, risk was higher among survivors of gynecologic cancers (odds ratio = 10.00, 95% confidence interval = 1.28-78.11) and those who had treatments directly or potentially affecting ovarian functioning (odds ratio = 13.00, 95% confidence interval = 1.70-99.36) compared with their respective co-twins.

CONCLUSIONS

These findings suggest that localized treatments and other cancer-related factors should be explored as determinants that underlie the association between cancer diagnosis and long-term cognitive impairment.

Management of treatment-related symptoms in patients with breast cancer

Although the benefits of current treatment strategies are well established, many cancer survivors are at risk for developing physiologic and psychological late effects of cancer treatment that might lead to premature mortality and morbidity and compromise their quality of life. Psychological symptoms include anxiety, depression, fatigue, difficulty sleeping, and loss of self-esteem. Physiologic symptoms include pain, numbness, cognitive impairment, weight gain, loss of sexual interest, spontaneous menopause, and peripheral neuropathy. Both length and quality of survival are important end points. The goal of this review is to summarize the psychological and physiologic symptoms related to breast cancer treatment; the prevalence, contributing therapies, and inter-relatedness of these symptoms; current interventions to prevent, ameliorate, or treat these symptoms; and effectiveness and safety of these interventions. The results of this review will identify the gaps in knowledge and assist in the design of assessments and approaches to improve mortality and quality of life and provide the foundation for the development of evidence-based guidelines to standardize palliative care in cancer survivors.

Evaluation of multiple neurotoxic outcomes in cancer chemotherapy

Although it is now clear that cognitive dysfunction is a common accompaniment of cancer chemotherapy, its implications await further research and direction. Most of the clinical research relies on standard neuropsychological tests that were developed to diagnose stable traits. Cognitive dysfunction in patients undergoing treatment varies with time, however. Its dimensions will vary during the course of treatment, which generally consists of cycles of drug administration followed by recovery periods. To effectively determine the connection between chemotherapy and cognitive function requires neuropsychological tests based on performance, so that they can be administered repeatedly at specified times during the entire course of treatment and beyond. A number of computerized test batteries, many of which have been developed for environmental neurotoxicology, are now available that fit such criteria. Moreover, cognitive impairment is only one aspect of chemotherapy-induced neurotoxicity. A full appreciation of its scope requires assessment of sensory functions such as vision, audition and somatosensory properties and assessment of motor function. A program of research based on animal models is also essential. Only with animal models is it possible to determine dose-response relationships and to couple behavioral with mechanistic indices such as neuroplasticity. Animal behavior models play a vital role in environmental toxicology because, from them, it is possible to derive some index of exposure that limits adverse effects. However, as in human testing, it is critical to choose situations whose properties remain stable over long periods of time so as to trace the time course of neurotoxicity. Schedule-controlled operant behavior offers the most promising source of animal models.

Cognitive changes associated with endocrine therapy for breast cancer

Endocrine therapy in the setting of breast cancer has undoubtedly advanced clinical outcomes in this disease, but treatment with endocrine therapy is accompanied by a wide spectrum of side effects. It is of prime importance to understand and characterize these toxicities to facilitate clinical decision-making. Somewhat surprisingly, there is a relative paucity of data pertaining to cognitive changes associated with endocrine therapy. In this article we review cognitive associated with two classes of endocrine therapy: (1) selective estrogen receptor modulators (SERMs; tamoxifen and raloxifene) and (2) aromatase inhibitors (AIs; anastrozole, letrozole, and exemestane). Companion studies to the Multiple Outcome of Raloxifene Evaluation (MORE), the Study of Tamoxifen and Raloxifene (STAR) and National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1 trials provide relevant data to understand the effect of SERMs on cognition. In contrast, substudies of the Arimidex, Tamoxifen Alone or in Combination (ATAC), Tamoxifen and Exemestane Adjuvant Multinational (TEAM) and Breast International Group (BIG) 1-98 trials juxtapose cognitive effects of AIs against those of tamoxifen. These and other studies are examined herein to provide a comprehensive overview of the effect of endocrine therapy on cognition.

Adjuvant aromatase inhibitor therapy: outcomes and safety

Adjuvant therapy with the third-generation aromatase inhibitors (AIs) anastrozole, letrozole, and exemestane has largely replaced the use of tamoxifen (TAM) as standard adjuvant endocrine treatment for postmenopausal women with hormone-sensitive early breast cancer. Treatment strategies investigated in large, randomized, well-controlled clinical studies include the use of an AI as an upfront replacement for TAM, as an alternative to continued treatment with TAM, and in the extended adjuvant setting after at least 5 years of TAM. The efficacy of AIs over TAM has been demonstrated, particularly in terms of improving disease-free survival (DFS), and reductions in early distant metastasis with AIs may ultimately translate into improved overall survival. As AI therapy offers prolonged DFS, safety is an important concern over the long term. The AIs are better tolerated than TAM in terms of troublesome gynecologic adverse events such as vaginal bleeding and discharge, as well as life-threatening complications such as venous thromboembolic events and endometrial cancer. On the other hand, AI therapy has been associated with losses in bone density and a potential effect on lipids and cardiovascular risk. In trials comparing AIs with TAM, only limited conclusions can be made because of the putative cardioprotective, lipid-lowering, and bone-sparing effects of TAM. Studies comparing AIs with placebo, and/or in healthy women, may be more useful in understanding the long-term safety of adjuvant AI therapy. Results of ongoing safety analyses within some of the large AI trials should provide further insight into the long-term tolerability of AI therapy in the adjuvant setting.

Cognitive and psychological factors associated with early posttreatment functional outcomes in breast cancer survivors

Breast cancer survivors experience cognitive difficulties following chemotherapy, yet the effects of these deficits on functional outcomes have not been systematically evaluated. This study assessed the relationships between postchemotherapy cognitive difficulties and functional outcomes. Forty-six women with breast cancer were seen at 1-month postchemotherapy; data were collected on cognitive functioning, psychological variables, and physical symptoms. Wilcoxon signed-rank analyses revealed cognitive deficits in executive functioning and verbal fluency. Subsequent regression analyses demonstrated that poorer executive functioning was associated with decreased productivity, community involvement, and social role functioning. Poorer quality of life was predicted by depression and reluctance to seek social support, but not cognitive functioning. These findings indicate that executive functioning deficits are associated with important functional outcomes among breast cancer survivors 1-month postchemotherapy. Thus, treatment efforts should focus on addressing cognitive, as well as psychological and physical, issues among cancer survivors.

The expanding use of third-generation aromatase inhibitors: what the general internist needs to know

BACKGROUND

Breast cancer patients represent the largest group of adult cancer survivors in the US. Most breast cancers in women 50 years of age and older are hormone receptor positive. Third generation aromatase inhibitors (AIs) are the newest class of drugs used in treating hormone responsive breast cancer. It is often during start of adjuvant hormone therapy that the breast cancer patient establishes (or reestablishes) close follow-up with their general internist.

OBJECTIVE

Given the large numbers of breast cancer patients in the US and the increasing use of third generation AI's, general internists will need to have a clear understanding of these drugs including their benefits and potential harms. Currently there are three third generation aromatase inhibitors FDA approved for use in the US. All have been shown to be superior to tamoxifen in disease free survival (DFS) in the treatment of both metastatic and early breast cancers.

RESULTS

While the data on side effects is limited, AI (compared to tamoxifen) may result in higher rates of osteoporosis and fractures, more arthralgias, and increased vaginal dryness and dysparuenia. Limited information on their effects on the cardiovascular system and neuro-cognitive function are also available. Patient's receiving adjuvant hormone therapy are generally considered disease free or disease stable and require less intensive monitoring by their breast cancer specialist.

CONCLUSIONS

In situations where patients experience significant negative side effects from AI therapy, discussions to discontinue treatment (and switch to an alternative endocrine therapy) should involve the cancer specialist and take into consideration the patient's risk for breast cancer recurrence and the impact of therapy on their quality of life. In some cases, patients may choose to never initiate AI treatment. In other cases, patients may choose to prematurely discontinue therapy even if therapy is well tolerated. In both settings increased knowledge by the general internists will likely facilitate discussions of risks versus benefits of therapy and possibly improve compliance to adjuvant hormone therapy.

Long-term efficacy and safety of letrozole for the adjuvant treatment of early breast cancer in postmenopausal women: a review

Aromatase inhibitors (AIs) are becoming more widely used than tamoxifen as adjuvant hormonal therapy for postmenopausal women (PMW) with early breast cancer (EBC). It is clear that these drugs offer important efficacy benefits over tamoxifen and differ from tamoxifen in their safety profile. The accepted strategies for adjuvant AI therapy include initial adjuvant treatment following surgery, switching and/or sequencing from prior tamoxifen, and extended adjuvant therapy following the full 5 years of tamoxifen treatment. Among the available AIs, letrozole has been evaluated in large, well-controlled, double-blind clinical trials in the initial adjuvant, extended adjuvant, and more recently, the sequential adjuvant settings. Letrozole is the most potent of the AIs and provides near complete suppression of plasma estrogens in PMW. Letrozole also significantly reduces the occurrence of early distant metastases, the most lethal type of recurrence event, which can lead to improved survival. Clinical comparisons of letrozole with both tamoxifen and placebo have also provided important long-term safety data on the use of AIs as adjuvant therapy in PMW with EBC. The weight of clinical evidence indicates that letrozole is a safe and effective option for adjuvant hormonal therapy across all three AI treatment settings.

Prechemotherapy alterations in brain function in women with breast cancer

Despite clinical reports of cognitive deficits associated with cancer chemotherapy, the underlying brain mechanisms are not clear. This research examined selective attention and working memory using functional magnetic resonance imaging (fMRI) in women before chemotherapy for localized breast cancer. Patients were tested with an established selective attention and working memory task during fMRI. Compared with healthy controls, patients showed (a) bilateral brain activation in high-demand task conditions with recruitment of additional components of attention/working memory circuitry, and (b) less accurate and slower task performance. Results indicate compromised cognitive functioning before any chemotherapy and raise key questions for further research.

The effect of modafinil on cognitive function in breast cancer survivors

BACKGROUND

The authors conducted a randomized clinical trial examining the effects of modafinil in reducing persistent fatigue in patients after treatment for cancer and performed secondary analyses to assess the effect of modafinil on cognitive function.

METHODS

Breast cancer patients who reported a score of >or=2 on the Brief Fatigue Inventory were enrolled in the study. In phase 1 (P1), patients received 200 mg modafinil open-label once daily for 4 weeks. In phase 2 (P2), patients with a positive response after P1 were randomized either to an additional 4 weeks of modafinil or to placebo. Tests of memory and attention selected from the Cognitive Drug Research (CDR) computerized cognitive assessment were performed at baseline (before modafinil) and after completing phases 1 and 2. The paired differences for each test score were subjected to a Wilcoxon signed rank test.

RESULTS

Of the 82 women who were enrolled, 76 completed P1, and 68 completed all assessments in the study. Modafinil had a significant effect on the Speed of Memory (P = .0073) and Quality of Episodic Memory (P < .0001) during P1 of the study. After randomization at Week 8, those patients who continued modafinil demonstrated significantly greater improvement in Speed of Memory (P = .029), Quality of Episodic Memory (P = .0151), and mean Continuity of Attention (P = .0101) relative to the group that was switched to placebo.

CONCLUSIONS

The authors found that modafinil improved cognitive performance in breast cancer survivors by enhancing some memory and attention skills. Although confirmation is needed, these findings suggest that modafinil may enhance quality of life in this patient population.

Oncologist use of the Adjuvant! model for risk communication: a pilot study examining patient knowledge of 10-year prognosis

Background

Our purpose was to collect preliminary data on newly diagnosed breast cancer patient knowledge of prognosis before and after oncology visits. Many oncologists use a validated prognostic software model, Adjuvant!, to estimate 10-year recurrence and mortality outcomes for breast cancer local and adjuvant therapy. Some oncologists are printing Adjuvant! screens to use as visual aids during consultations. No study has reported how such use of Adjuvant! printouts affects patient knowledge of prognosis. We hypothesized that Adjuvant! printouts would be associated with significant changes in the proportion of patients with accurate understanding of local therapy prognosis.

Methods

We recruited a convenience sample of 20 patients seen by 2 senior oncologists using Adjuvant! printouts of recurrence and mortality screens in our academic medical center. We asked patients for their estimates of local therapy recurrence and mortality risks and counted the number of patients whose estimates were within ± 5% of Adjuvant! before and after the oncology visit, testing whether pre/post changes were significant using McNemar's two-sided test at a significance level of 5%.

Results

Two patients (10%) accurately estimated local therapy recurrence and mortality risks before the oncology visit, while seven out of twenty (35%) were accurate afterwards (p = 0.125).

Conclusion

A majority of patients in our sample were inaccurate in estimating their local therapy recurrence and mortality risks, even after being shown printouts summarizing these risks during their oncology visits. Larger studies are needed to replicate or repudiate these preliminary findings, and test alternative methods of presenting risk estimates. Meanwhile, oncologists should be wary of relying exclusively on Adjuvant! printouts to communicate local therapy recurrence and mortality estimates to patients, as they may leave a majority of patients misinformed.

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.

Effect of epoetin alpha therapy on cognitive function in anaemic patients with solid tumours undergoing chemotherapy

The primary aim of this study was to assess whether epoetin alpha (Ea) would improve cognitive performance in a group of anaemic cancer patients receiving chemotherapy. The secondary aim was to confirm the positive impact of Ea on haematological parameters, and quality of life (QOL). Fifty patients with solid tumours and haemoglobin (Hb) <11.0 g/dL received Ea 40,000 units once weekly for 12 weeks and were administered the Mini-Mental State Examination and the European Organization for Research and Treatment of Cancer (QLQ-C30) questionnaire prior to Ea therapy and at study completion. No clinically significant alterations were observed on cognitive function during Ea treatment. Changes in cognitive function were unrelated to Hb change and there were no significant differences in cognitive performance between Ea responders and non-responders. The analyses revealed clinically significant improvements in Hb levels, physical and role function, and clinically meaningful reductions in fatigue. Hb changes were significantly associated with the magnitude of improvement in QOL parameters. The lack of a clinical benefit in cognition observed in this study during Ea treatment may redirect the focus of research from enhancing to maintaining cognitive function, since stability in cognitive performance through time may be as well clinically important.

Deterioration of quality of life of high-risk breast cancer patients treated with high-dose chemotherapy: the PEGASE 01 Quality of Life Study

OBJECTIVE

The aim of this study was to compare the quality of life (QOL) of high-risk breast cancer patients included in a randomized clinical trial (PEGASE 01) comparing conventional chemotherapy versus adding an additional high-dose chemotherapy (HDC) cycle with blood stem cell support.

METHODS

A total of 314 patients were included in the clinical trial. QOL evaluations were available for 199 patients. QOL was assessed over a 1-year follow-up period, using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C-30. The results were analyzed using a linear mixed-effects model.

RESULTS

Toxicity of HDC has a strong negative impact on patients' QOL during the treatment phase. This negative impact tended to last longer in the HDC group, as for most of the QLQ-C30 scales, the QOL scores of HDC patients tend to improve at a slower rate than that of patients receiving standard chemotherapy. In particular, physical functioning remains deteriorated 1 year after inclusion for HDC patients comparatively to conventional chemotherapy patients (85.99 vs. 76.65, P = 0.021), and the pain score was still higher in the HDC group at that time (28.32 vs. 15.97, P = 0.004).

CONCLUSION

HDC has a negative impact on QOL even after treatment phase. In the absence of an overall survival benefit of using HDC for high-risk breast cancer patients, QOL studies with a longer follow-up play an important role in informing the complex trade-off implied by HDC between higher toxicity, reduced risk of relapse, and QOL decrease after the active phase of treatment.

The intersection of cancer and aging: establishing the need for breast cancer rehabilitation

The increasing success of treatments for common cancers has resulted in growing awareness of the unique health care needs of cancer survivors. Cancer treatments can be toxic and have long-lasting effects on health, potentially accelerating the aging process and producing associated declines in physical function. In this synthesis of the literature, we critically examine the strength of existing evidence that breast cancer diagnosis and treatment are associated with a disproportionate decline in physical function compared with the effects of living without cancer for the same number of years. There is some observational epidemiologic evidence that women treated for breast cancer report greater declines in physical function than their peers. Discerning the factors associated with such declines and their clinical significance remains to be addressed. Physiologic, psychological, and behavioral changes associated with both aging and cancer treatment are reviewed. Parallels are proposed between existing preventive and rehabilitative programs and possibilities for similar interventions aimed at preventing, reversing, or halting declines in physical function in cancer survivors. Finally, a program of research is proposed to evaluate whether there is some subset of breast cancer survivors for whom prevention or rehabilitation of functional status declines is needed, as well as development of targeted, mechanistically driven interventions.

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.

Evaluation of Cognitive Function Associated With Chemotherapy: A Review of Published Studies and Recommendations for Future Research

Purpose

There is evidence that some cancer survivors suffer cognitive impairment after chemotherapy. Determining if a patient has cognitive impairment is challenging, especially because impairment is usually subtle.

Patients and Methods

We assessed the design of studies evaluating cognitive function during or after chemotherapy in adult patients with solid tumors. We also reviewed methods used to evaluate cognitive function in subjects with other diseases and make recommendations for future studies.

Results

We identified 22 studies that met our criteria: 82% included women with breast cancer. Eight studies were longitudinal, 12 were cross-sectional, and two were follow-ups of cross-sectional studies. Sixteen studies used a battery of neuropsychological (NP) tests to assess subjects, and 13 included a control group. Ten studies (45%) had no explicit definition of cognitive impairment; most others used z scores or T scores and defined impairment based on standard deviations below the mean, but there was no consistency in for the cutoff point used or the number of tests required.

Conclusion

There is no consistency in defining cognitive impairment, in the NP batteries used, or in statistical methods in studies of cognitive function of cancer patients. We suggest guidelines to define criteria for cognitive impairment. Use of summary scores and control groups is recommended. Practice effect should be adjusted for in longitudinal studies. A balance is needed between comprehensive batteries and briefer tests, which still need to be sensitive to mild impairment.

Smaller regional volumes of brain gray and white matter demonstrated in breast cancer survivors exposed to adjuvant chemotherapy

BACKGROUND

Previous studies have shown cognitive impairment in breast cancer survivors who were exposed to adjuvant chemotherapy. Neural damage by chemotherapy might have played some part in these findings. The current study explored the regional brain volume difference between breast cancer survivors exposed to adjuvant chemotherapy (C+) and those unexposed (C-).

METHODS

High-resolution 1.5-tesla brain magnetic resonance imaging (MRI) databases of breast cancer survivors and healthy controls were used. Brain images were preprocessed for optimal voxel-based morphometry. Comparisons of gray matter and white matter were performed between the C+ and the C- groups, by using MRI scans from within 1 year (the 1-year study, n = 51 and n = 55, respectively) or 3 years after their cancer surgery (the 3-year study, n = 73 and n = 59, respectively). As exploratory analyses, correlation analyses were performed between indices of the Wechsler Memory Scale-Revised and regional brain volume where the volume were significantly smaller. As a reference, MRI scans of cancer survivors were compared with those of healthy controls (n = 55 for the 1-year study and n = 37 for the 3-year study).

RESULTS

The C+ patients had smaller gray matter and white matter including prefrontal, parahippocampal, and cingulate gyrus, and precuneus in the 1-year study. However, no difference was observed in the 3-year study. The volumes of the prefrontal, parahippocampal gyrus, and precuneus were significantly correlated with indices of attention/concentration and/or visual memory. Comparisons with healthy controls did not show any significant differences.

CONCLUSIONS

Adjuvant chemotherapy might have an influence on brain structure, which may account for previously observed cognitive impairments.

Psychometric properties of a tool for measuring hormone-related symptoms in breast cancer survivors

Hormone-related symptoms are common in breast cancer survivors and many aspects of these symptoms are currently under study. Reliable and valid assessment tools are needed to successfully study hormone-related symptoms in breast cancer survivors; however, no gold standard currently exists for measuring these symptoms. This study evaluated the psychometric properties of a shortened version of the Breast Cancer Prevention Trial (BCPT) symptom checklist in a sample of 803 breast cancer survivors. Principal factor analysis with Promax oblique rotation revealed a five-factor structure, identifying five separate hormone-related symptoms scales: vasomotor symptoms, urinary incontinence, cognitive/mood changes, vaginal symptoms, and weight gain/appearance concern. Hormone-related symptom scale scores differed by demographic and clinical characteristics according to expectations, suggesting that these five scales from the shortened BCPT checklist are reasonably reliable and valid. Symptom scale scores were only weakly correlated with health-related quality of life scores; however, the pattern of results generally supported the validity of the symptom scales. This study adds to the evidence that breast cancer survivors experience a significant number of hormone-related symptoms. Future clinical trials and quality of life and symptom management intervention studies would benefit from accurate assessment of hormone-related symptoms with the five scales from the shortened BCPT checklist.

Exercise for women receiving adjuvant therapy for breast cancer

BACKGROUND

A huge clinical research database on adjuvant cancer treatment has verified improvements in breast cancer outcomes such as recurrence and mortality rates. On the other hand, adjuvant therapy with agents such as hormone therapy, chemotherapy and radiotherapy impacts on quality of life due to substantial short- and long-term side effects.

OBJECTIVES

To assess the effect of aerobic or resistance exercise interventions during adjuvant treatment for breast cancer on treatment-related side effects such as physical deterioration, fatigue, psychosocial distress and physiological, morphological and biological changes.

SEARCH STRATEGY

We searched the Cochrane Breast Cancer Specialised Register (16 July 2004) and the following electronic databases: MEDLINE (1966 to 2006), EMBASE (1988 to 2004), CINAHL (1982 to 2004), SPORTDiscus (1975 to 2004), PsycINFO (1872 to 2003), SIGLE (1880 to 2004), ProQuest Digital Dissertations (1861 to 2004) and Conference Papers Index (1973 to 2004). Furthermore, we screened references in relevant reviews and clinical trials and handsearched relevant journals.

SELECTION CRITERIA

We included randomised and non-randomised controlled trials that examined aerobic or resistance exercise, or both, in women undergoing adjuvant treatment for breast cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed methodological quality and adequacy of the training stimulus following a set of standardised criteria. Meta-analyses were performed for physical fitness, fatigue and weight gain using a random-effects model.

MAIN RESULTS

Nine trials involving 452 women met the inclusion criteria. Meta-analysis for cardiorespiratory fitness (involving 207 participants) suggested that exercise improves cardiorespiratory fitness (SMD 0.66, 95% CI 0.20 to 1.12). Meta-analysis for fatigue (317 participants) found statistically non-significant improvements for participants in the exercise intervention groups compared to control (non-exercising) groups (SMD -0.12, 95% CI -0.37 to 0.13); the same applied for the meta-analysis of weight gain (147 participants) (SMD -1.11, 95% CI -2.44 to 0.22). Evidence for other outcomes remains limited. Adverse effects (lymphedema and shoulder tendonitis) were observed in two trials. The results from non-randomised controlled trials are similar to those of randomised controlled trials and do not appear to produce any bias. This review is based on a small number of trials with a considerable degree of clinical heterogeneity regarding adjuvant cancer treatments and exercise interventions.

AUTHORS' CONCLUSIONS

Exercise during adjuvant treatment for breast cancer can be regarded as a supportive self-care intervention which results in improved physical fitness and thus the capacity for performing activities of daily life, which may otherwise be impaired due to inactivity during treatment. Improvements in fatigue were ambiguous and there was a lack of evidence for improvement with exercise for other treatment-related side effects. Since exercise interventions (for sedentary participants) require behaviour change, strategies for behaviour change should underpin these interventions. Furthermore, long-term evaluation is required due to possible long-term side effects.

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

Given the improvement in mortality rates associated with breast cancer, the importance of understanding the long-term neuropsychological consequences of chemotherapy is becoming increasingly vital. This study applies meta-analytic techniques to the scant literature on the relationship between contemporary adjuvant chemotherapy treatment for breast cancer and cognitive dysfunction as examined through neuropsychological indices. Seven studies (involving more than 300 participants) were selected from over 200 potential articles, based on three inclusion criteria: presence of breast cancer, administration of chemotherapy treatment, and use of neuropsychological tests. From these, nine treatment-control comparisons were used to generate 129 Hedge's d effect sizes across the cognitive domains of simple attention, working memory short- and long-term memory, speed of processing, language, spatial abilities, and motor function. Small to medium cumulative effect sizes, showing diminished cognitive function for chemotherapy treatment groups compared to control groups, were obtained for each of the eight cognitive domains. Overall, these results suggest that women who undergo adjuvant chemotherapy as treatment for breast cancer may experience subtle yet consequential cognitive decline.

The phenomenon of chemo brain

During and following chemotherapy, some patients experience difficulties with memory, attention, and other aspects of cognitive function. This constellation of deficits commonly is referred to as chemo brain. Although the phenomenon is not understood completely, it is assuming greater significance as cancer survival improves. Return to prediagnosis levels of domestic, employment, and academic activity is expected in most survivors. Advances in basic, imaging, and clinical sciences are beginning to unravel pathophysiologic mechanisms and develop neuroprotective strategies. Pharmacologic options are borrowed from diverse diseases, including attention-deficit/hyperactivity disorder and neurodegenerative diseases. Conventional therapies soon may find new applications; for example, recent preclinical data suggest that erythropoietin may have some neuroprotective abilities, which may positively affect patients experiencing chemo brain. A collaborative model is bringing together international specialists interested in unraveling the mysteries of the phenomenon and developing management strategies to attenuate its effects. This article will review the clinical features of chemo brain as well as a working hypothesis regarding pathophysiology. The potential and emerging interventions that can be used by oncology nurses to assist patients and their families to cope with this enigmatic dysfunction will be discussed.

Cognitive functioning after adjuvant chemotherapy and/or radiotherapy for early-stage breast carcinoma

BACKGROUND

Evidence suggests that women diagnosed with early-stage breast carcinoma may experience cognitive problems as a consequence of adjuvant chemotherapy treatment. The present study was conducted to examine whether there are differences in cognitive performance and cognitive complaints between women treated with and without chemotherapy for TNM Stage 0 to II breast carcinoma.

METHODS

As part of a larger study on quality of life, women were recruited with newly diagnosed Stage 0 to II breast carcinoma scheduled to be treated with chemotherapy plus radiotherapy (n = 60) or radiotherapy only (n = 83). Six months after the completion of treatment, participants were administered a standard neuropsychologic battery to assess cognitive performance and a self-report measure to assess perceived cognitive problems.

RESULTS

There were no statistically significant differences between women who received chemotherapy and those who did not with regard to their average performance on tests of episodic memory, attention, complex cognition, motor performance, or language. Likewise, there were no significant differences between the treatment groups in the prevalence of impairment in each of these cognitive domains. Women who underwent chemotherapy also did not report significantly more problems with cognitive functioning than women treated without chemotherapy.

CONCLUSIONS

The findings failed to confirm previous reports suggesting adjuvant chemotherapy is associated with problems in cognitive functioning among women who receive treatment for Stage 0 to II breast carcinoma. Future research should use prospective longitudinal research designs incorporating appropriate comparison groups to further explore this issue.

A metaanalysis of studies of the effects of cancer chemotherapy on various domains of cognitive function

BACKGROUND

Little is known about the effects of chemotherapy on cognitive function. The purposes of this metaanalysis were to estimate the effect sizes for the effect of chemotherapy on each domain of cognitive function and to differentiate effect sizes by each method of comparison of effects (i.e., normative data, control group, or baseline data).

METHODS

Sixteen studies that evaluated cognitive function in chemotherapy patients were included in the study. DSTAT metaanalysis software was used to calculate an effect size and confidence intervals for each neuropsychologic test. Tests were assigned to a specific cognitive domain, and an average effect size was determined for each domain.

RESULTS

Only one domain of cognitive function (i.e., visual memory) had significant chemotherapy-induced impairment across all comparison types. However, when the neuropsychologic test scores of chemotherapy patients were compared with normative data, significant effect sizes were found for four domains of cognitive function (i.e., executive function, information processing speed, verbal memory, visual memory). In addition, significant, albeit small, effect sizes were found for language and verbal memory when chemotherapy patients' test scores were compared with test scores of healthy matched controls. All significant averaged effect sizes were in the negative direction, indicating that mean scores on neuropsychologic tests for patients who had received chemotherapy were on average lower than comparison scores.

CONCLUSION

Data from this metaanalysis supported the hypothesis that chemotherapy can have a negative impact on cognitive function. However, most deficits in this study ranged from small to moderate and were nonsignificant.

Cognitive effects of cytotoxic cancer chemotherapy: predisposing risk factors and potential treatments

Increasing evidence suggests that systemic cancer chemotherapy can have significant long-term effects on cognition, particularly on verbal learning, memory, attention, and speed of information processing. These deficits can be a source of significant distress to survivors. There is much less known about the mechanisms, predisposing vulnerabilities, and treatment of these deficits. We will summarize current knowledge of chemotherapy-associated cognitive deficits. Emerging theories about the role of selected genetic polymorphisms in heightening the vulnerability to chemotherapy-induced cognitive decline will be described.

Prospective assessment of emotional distress, cognitive function, and quality of life in patients with cancer treated with chemotherapy

BACKGROUND

The current study sought to delineate prospectively the rates and clinical course of emotional distress, cognitive impairment, and quality of life (QOL) in chemotherapy-naive patients with cancer and to consider the determinants of global QOL.

METHODS

Patients who consented to participate were administered the European Organization for Research and Treatment of Cancer QLQ-C30 questionnaire, the Mini-Mental State Examination (MMSE), and the Hospital Anxiety and Depression Scale before and at the end of treatment (EOT).

RESULTS

Of the 102 patients initially assessed, 80 (78.4%) completed the study. Most aspects of QOL did not change considerably over time. At EOT, patients reported only significant increases in fatigue and significant decreases in sleep disturbance. Although no significant changes emerged in the rates of anxiety or depression throughout chemotherapy, nearly one-third of the patients experienced severe emotional distress at both points in time. In addition, the authors observed neither significant alteration in the cognitive performance over time nor reliable associations between scores on the MMSE and subjective cognitive function, emotional distress, or QOL. Finally, depression proved to be the leading predictor of global QOL at baseline and at EOT.

CONCLUSIONS

The results indicated that a significant proportion of Greek patients with cancer experienced intense anxiety and depression throughout chemotherapy and confirmed the importance of depression as a strong predictor of global QOL. Routine screening of emotional distress across all phases of cancer is mandatory because it will contribute to the identification of patients who are in need of pharmaceutical and/or psychologic intervention.