Change in cognitive function after chemotherapy: a prospective longitudinal study in breast cancer patients

Chemotherapy-Related Change in Cognitive Function: A Conceptual Model

PURPOSE/OBJECTIVES

To develop a conceptual model of chemotherapy-related changes in cognitive function.

DATA SOURCES

MEDLINE, CINAHL, HealthStar, and PsycINFO databases.

DATA SYNTHESIS

Patients undergoing chemotherapy often complain of forgetfulness, absentmindedness, and an inability to focus when performing a variety of daily tasks. Changes in cognitive function have been referred to by the colloquial term "chemo-brain." The authors conducted an examination of the literature to investigate relationships among concepts and to synthesize current knowledge.

CONCLUSIONS

Cognitive function, defined as higher-order mental processes, may be altered along two distinct and interacting pathways: (a) the cancer diagnosis, which can lead to anxiety, stress, distress, and depression; and (b) the direct physiologic effects of cancer treatment. The Chemotherapy-Related Change in Cognitive Function conceptual model is informed by a review of literature that illustrates antecedents, moderators, mediators, and consequences that may be relevant to this issue.

IMPLICATIONS FOR NURSING

When a patient presents with cognitive complaints, the problems can be evaluated for intervention when an overall understanding exists of chemotherapy-related cognitive changes based on a conceptual model that continues to be informed through well-conceptualized and well-designed research.

Cognitive dysfunction associated with chemotherapy for breast cancer

Cognitive dysfunction occurs in at least one-fifth (and by some reports, more than four-fifths) of breast-cancer patients who previously underwent adjuvant therapy with cytotoxic pharmacologic regimens. The main purpose of this report is to define the scope of the cognitive problems suffered by cancer patients who were previously exposed to cytotoxic chemotherapy, which have come to be grouped under the conceptual umbrella of 'chemobrain'. Second, we aim to spotlight the present inadequacy of clinical care in dealing with chemobrain-related issues – with respect both to the sins of omission of oncologists in obtaining informed consent for the cytotoxic therapies they are planning to prescribe, as well as to the subsequent failure of healthcare providers to address chemobrain-related problems experienced by a substantial proportion of their patients. Finally, we will examine how current investigations employing the tools of neuropsychologic and neuroimaging instruments are figuratively and literally shedding new light (and other wavelengths of the electromagnetic spectrum) on the brains of living chemotherapy-treated subjects, leading to an increased understanding of the chemobrain problem, as well as pointing the way to strategies for diminishing its future impact.