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Understanding on the association between informal caregiver characteristics and cognitive function of adults with cancer: a scoping review protocol

INTRODUCTION

Adults with cancer frequently report symptoms such as decline in cognitive function throughout the trajectory of illness. Patients with cognitive deficits need support and assistance from their informal caregivers and often rely on them to manage their symptoms based on their degree of deficits. Patients spend a significant amount of time with their informal caregivers and become interdependent with each other. In spite of their interdependence, it is unclear whether patients' cognitive outcomes (ie, cognitive function) are associated with their informal caregivers. Therefore, the body of literature related to the association between caregiver characteristics and cognitive function of adults with cancer needs to be fully mapped with assessment for knowledge gaps.

METHODS AND ANALYSIS

Methods for this scoping review was informed by the framework proposed by Arksey and O'Malley. Seven electronic databases will be searched: (1) PubMed (MEDLINE), (2) CINAHL, (3) Embase, (4) PsycINFO, (5) Scopus, (6) Sociological Abstracts and (7) ProQuest dissertation abstracts. In addition, the search for grey literature will include the conference abstracts available through Embase, Scopus and Sociological abstracts as well as dissertations available in ProQuest dissertations. All retrieved citations will be independently screened by two authors and eligibility will be determined based on inclusion and exclusion criteria at title and abstract level. Studies meeting inclusion criteria, will be screened at full text level by two reviewers followed by abstraction of included studies. Eligible studies will be collated, summarised and reported using the data charting form that research team developed.

ETHICS AND DISSEMINATION

This scoping review does not require ethics approval. Results of this scoping review will be disseminated via conference presentation and/or publication in a scientific journal.

Developing interventions for cancer-related cognitive dysfunction in childhood cancer survivors

Survivors of childhood cancer frequently experience cancer-related cognitive dysfunction, commonly months to years after treatment for pediatric brain tumors, acute lymphoblastic leukemia (ALL), or tumors involving the head and neck. Risk factors for cancer-related cognitive dysfunction include young age at diagnosis, treatment with cranial irradiation, use of parenteral or intrathecal methotrexate, female sex, and pre-existing comorbidities. Limiting use and reducing doses and volume of cranial irradiation while intensifying chemotherapy have improved survival and reduced the severity of cognitive dysfunction, especially in leukemia. Nonetheless, problems in core functional domains of attention, processing speed, working memory and visual-motor integration continue to compromise quality of life and performance. We review the epidemiology, pathophysiology and assessment of cancer-related cognitive dysfunction, the impact of treatment changes for prevention, and the broad strategies for educational and pharmacological interventions to remediate established cognitive dysfunction following childhood cancer. The increased years of life saved after childhood cancer warrants continued study toward the prevention and remediation of cancer-related cognitive dysfunction, using uniform assessments anchored in functional outcomes.

Cognitive impairments and cancer chemotherapy: translational research at a crossroads

Cancer chemotherapy is often associated with cognitive deficits which may remain after the treatment has ended. As more people survive cancer, concern is increasing about the impact of these problems with memory and executive function when they return to everyday life. When chemotherapeutic drugs are administered to healthy animals in dosing regimens modeling those used in humans, cognitive deficits also occur, and these preclinical studies can provide information about the biological mechanisms by which the cancer fighting drugs affect the brain. Evidence from animal studies points to damage to hippocampus, particularly a disruption of neurogenesis, whereas human studies emphasize cognitive deficits associated with impairments in frontal cortical function. This discrepancy may be due more to the tasks selected by researchers, and the choice of biochemical endpoints than inherently different effects of chemotherapy in humans and rodents. These differences in approach must be reconciled if common underlying mechanisms are to be identified, with the hope of leading to novel drug or non-pharmacological treatments. This may be achieved by broadening the scope of human and animal studies, and by looking outside the topic of chemotherapy-induced cancer deficits to learn from the advances being made by studying the effects of stress and somatic disease on brain function, and the cognitive impairments now recognized to result from a wide range of mental and physical illnesses.