Cognitive Effects of Cancer and Cancer Treatments

As the population of cancer survivors has grown into the millions, there has been increasing emphasis on understanding how the late effects of treatment affect survivors' ability to return to work/school, their capacity to function and live independently, and their overall quality of life. This review focuses on cognitive change associated with cancer and cancer treatments. Research in this area has progressed from a pharmacotoxicology perspective to a view of the cognitive change as a complex interaction of aspects of the treatment, vulnerability factors that increase risk for posttreatment cognitive decline, cancer biology, and the biology of aging. Methodological advances include the development of (a) measurement approaches that assess more fine-grained subcomponents of cognition based on cognitive neuroscience and (b) advanced statistical approaches. Conceptual issues that arise from this multidimensional perspective are described in relation to future directions, understanding of mechanisms, and development of innovative interventions.

Cognitive dysfunction and cancer: which consequences in terms of disease management?

OBJECTIVES

The aim of this review is to stress the importance of cognitive dysfunction in cancer survivors, and to discuss the way of assessing and managing these troubles in clinical practice.

METHOD

Original studies and reviews reporting the effect of cancer and chemotherapy on cognition and published since January 2000 were selected from the Medline(®) database using 'cognition' or 'cognitive function' and 'cancer' as subject headings.

RESULTS

Main reports concerned women with advanced breast cancer or children with hematological or brain cancers. Overall, chemotherapy was found to be associated with subtle and transient cognitive dysfunctions, which were detectable only with neuropsychological testing and affected most particularly memory, concentration and speed of information processing. Some factors associated with the patient, like depression, may favor cognitive impairment, while the role of others, like age or educational level, remains to be defined. Screening of patients at risk remains limited due to the lack of standardized neuropsychological tests in clinical oncology practice. Few studies have addressed the benefits of interventional strategies but methylphenidate, modafinil and erythropoietin, as well as rehabilitation in children, have shown encouraging results. Formal studies assessing the value of a multidisciplinary approach to detect and manage cognitive impairment must be recommended.

CONCLUSION

Cognitive dysfunction induced by cancer or the treatment represents a real challenge in clinical practice. Based on limited published data, few clinical recommendations can be made regarding prevention, evaluation and management of this trouble. Longitudinal studies must be conducted to evaluate its real impact on quality of life.

Methylphenidate for fatigue in ambulatory men with prostate cancer

BACKGROUND

Fatigue is a highly prevalent and clinically significant symptom of advanced prostate cancer. To date, however, there are no published controlled trials of interventions for fatigue in men with prostate cancer.

METHODS

This 6-week, randomized, double-blind, placebo-controlled design evaluated the efficacy of methylphenidate to treat fatigue in prostate cancer patients. Inclusion criteria included men with advanced prostate cancer and the presence of moderate to severe fatigue. Patients with major depression, hypothyroidism, uncontrolled hypertension, arrhythmia, or anemia were excluded. Fatigue levels, blood pressure, pulse, and other safety concerns were monitored regularly.

RESULTS

Thirty-two subjects were randomized to methylphenidate (n=16) or placebo (n=16). Brief Fatigue Inventory total scores significantly decreased for both groups; however, the methylphenidate group, as compared with placebo, reported greater decrease on Brief Fatigue Inventory severity scores (P=.03) and a trend toward greater decrease on Brief Fatigue Inventory total scores (P=.07). A significantly greater number of subjects in the methylphenidate group versus the placebo group demonstrated clinically significant improvement in fatigue on total Brief Fatigue Inventory scores (7 of 10 vs 3 of 13) and Brief Fatigue Inventory severity scores (8 of 10 vs 3 of 13). Importantly, 6 subjects in the methylphenidate group discontinued because of increased blood pressure or tachycardia. There were no serious adverse events.

CONCLUSIONS

Methylphenidate is effective in treating fatigue in men with prostate cancer; however, oncologists need to monitor for possible pulse and blood pressure elevations.

Cancer-related fatigue

CRF is indisputably a significant problem with important public health and medical economic implications. As the prevalence of cancer survivorship grows, the impact of CRF will increase. Physiatrists have not historically played an active role in caring for affected patients. In the author's opinion, this is unfortunate, since the holistic, integrated, and cross-disciplinary approach that characterizes physiatry seems ideally suited to offer patients meaningful benefit. Physiatrists with a clinical interest are likely to be robustly rewarded with interest from the oncological community, as CRF is a frustrating and devastating problem for patients and clinicians alike.

Methylphenidate for the treatment of depressive symptoms, including fatigue and apathy, in medically ill older adults and terminally ill adults

BACKGROUND

Depressive symptoms, fatigue, and apathy are common symptoms among medically ill older adults and patients with advanced disease, and have been associated with morbidity and mortality. Methylphenidate has been used to treat these symptoms because of its rapid effect. Despite the long history of methylphenidate use for the treatment of depressive symptoms, fatigue, and apathy, there is little definitive evidence to support its use.

OBJECTIVE

The aim of this paper was to review the efficacy and tolerability of methylphenidate in the treatment of depressive symptoms, fatigue, and apathy in medically ill older adults and adults receiving palliative care.

METHODS

English-language articles presenting systematic reviews, clinical trials, or case series describing the use of methylphenidate for the treatment of depressive symptoms, fatigue, or apathy in medically ill older adults or adults receiving palliative care were identified. The key words methylphenidate and either depressive, depression, fatigue, or apathy were used to search the Cochrane Database, MEDLINE, PsycINFO, and International Pharmaceutical Abstracts. Included articles addressed depressive symptoms, fatigue, or apathy in (1) older adults (generally, age > or =65 years), particularly those with comorbid medical illness; (2) adults receiving palliative care; and (3) adults with other chronic illnesses. I excluded articles regarding treatment of depression in healthy young adults; bipolar disorder and attention-deficit/hyperactivity disorder; and narcolepsy, chronic fatigue syndrome, and related disorders.

RESULTS

A total of 19 controlled trials of methylphenidate in medically ill older adults or patients in palliative care were identified. Unfortunately, their conflicting results, small sample sizes, and poor methodologic quality limited the ability to draw inferences regarding the efficacy of methylphenidate, although evidence of tolerability was stronger. The available evidence suggests possible effectiveness of methylphenidate for depressive symptoms, fatigue, and apathy in various medically ill populations.

CONCLUSION

In the absence of definitive evidence of effectiveness, trials of low-dose methylphenidate in medically ill adults with depression, fatigue, or apathy, with monitoring for response and adverse effects, are appropriate.

Cancer fatigue: a review for psychiatrists

OBJECTIVE

Cancer-related fatigue (CRF) is a ubiquitous and debilitating phenomenon for patients both during and after treatment for cancer of all types. This review will outline the complex neurobiological mechanisms underlying CRF and their relevance to various treatment routes. It will cover aspects of screening, diagnosis and treatment, including both pharmacological and behavioral interventions for CRF. The goal of the article was not to perform a comprehensive literature review or meta-analysis, but rather to integrate clinically relevant information from different areas of research related to cancer fatigue, including etiology, diagnosis and management for a nonspecialist audience.

METHOD

The methodology used involved broadly surveying the literature available on Medline using such search terms as "cancer," "fatigue," "cytokine" and "depression," exploring relevant articles over the past 15 years and relevant citations from these articles and focusing on recent advances in the study of CRF.

RESULTS

CRF occurs at high prevalence rates during and subsequent to cancer treatment. Multidisciplinary approaches are available for the assessment and management of fatigue including underlying contributory factors.

CONCLUSIONS

An increasing base for evidence is present to guide the management of CRF. Additional research is warranted to understand the neurobiological mechanisms, etiology and risk factors for fatigue.

Breast Cancer and Fatigue

Fatigue is a common and disabling symptom in breast cancer patients and survivors. A rather nebulous concept, fatigue overlaps with sleepiness and depressed mood. In this chapter, we cover methods for assessing fatigue; describe the occurrence of fatigue before, during and after initial treatment; present possible underlying mechanisms of fatigue; and, enumerate approaches to its treatment.

A Phase III, Double-Blind, Placebo-Controlled Prospective Randomized Clinical Trial of d-Threo-Methylphenidate HCl in Brain Tumor Patients Receiving Radiation Therapy

PURPOSE

The quality of life (QOL) and neurocognitive function of patients with brain tumors are negatively affected by the symptoms of their disease and brain radiation therapy (RT). We assessed the effect of prophylactic d-threo-methylphenidate HCl (d-MPH), a central nervous system (CNS) stimulant on QOL and cognitive function in patients undergoing RT.

METHODS AND MATERIALS

Sixty-eight patients with primary or metastatic brain tumors were randomly assigned to receive d-MPH or placebo. The starting dose of d-MPH was 5 mg twice daily (b.i.d.) and was escalated by 5 mg b.i.d. to a maximum of 15 mg b.i.d. The placebo was administered as one pill b.i.d. escalating three pills b.i.d. The primary outcome was fatigue. Patients were assessed at baseline, the end of radiation therapy, and 4, 8, and 12 weeks after brain RT using the Functional Assessment of Cancer Therapy with brain and fatigue (FACIT-F) subscales, as well as the Center for Epidemiologic Studies Scale and Mini-Mental Status Exam.

RESULTS

The Mean Fatigue Subscale Score at baseline was 34.7 for the d-MPH arm and 33.3 for the placebo arm (p = 0.61). At 8 weeks after the completion of brain RT, there was no difference in fatigue between patient groups. The adjusted least squares estimate of the Mean Fatigue Subscale Score was 33.7 for the d-MPH and 35.6 for the placebo arm (p = 0.64). Secondary outcomes were not different between the two treatment arms.

CONCLUSIONS

Prophylactic use of d-MPH in brain tumor patients undergoing RT did not result in an improvement in QOL.

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.

Pharmacologic treatment of cancer-related fatigue

Fatigue is the most commonly reported symptom in patients with cancer, with a prevalence of over 60% reported in the majority of studies. This paper systematically reviews pharmacologic agents in the treatment of cancer-related fatigue (CRF). We conducted a literature review of clinical trials that assessed pharmacologic agents for the treatment of CRF. These agents include hematopoietics (for anemia), corticosteroids, and psychostimulants. Other therapeutic agents that are less well studied for CRF but are currently the focus of clinical trials include l-carnitine, modafinil, bupropion, and selective serotonin reuptake inhibitors such as paroxetine. Disclosure of potential conflicts of interest is found at the end of this article.

Management of fatigue in cancer patients

Cancer-related fatigue (CRF) is either a symptom or a syndrome depending on criteria for diagnosis. CRF is present in 20% to 30% of long-term cancer survivors and 80% to 90% during treatment and at the end of life. Assessment requires determining the presence, severity, and interference with daily activities. Different descriptors for fatigue (eg, tiredness, lack of vigor) measure different patient experiences. Associated factors such as depression, pain, insomnia, dyspnea, anemia, and deconditioning worsen CRF and should be treated if present. Associated factors that contribute to the severity of fatigue differ depending on the stage of cancer. Pharmacologic interventions include recombinant erythropoietin, psychostimulants, corticosteroid, anti-inflammatory drugs other than steroids, and L-carnitine. Advances in the management of CRF will require an understanding of the underlying mechanism before target-specific therapies can be developed.