A Systematic Review Focusing on Understanding the Effects of a Defined Set of Non-Modifiable Factors in Patients who Suffer from Chemotherapy Induced Cognitive Impairments or “Chemobrain”

Abstract

Background: As the population of cancer survivors increases, there are increasing reports of patients experiencing chemotherapy-induced cognitive impairment (CICI). About 75% of cancer patients experience CICI during or after treatment; from that 75%, up to 35% will have persistent CICI for years following their initial treatment. The objective of this review is to discuss how non-modifiable factors (NMF) can be used in clinical settings to predict the severity of CICI in both cancer patients and cancer survivors. The NMFs this publication focuses on are demographics, genetics, inflammation, changes to brain structure, and type of cancer. The authors hope this information will benefit future clinicians by informing how certain NMFs predispose patients to CICI. Methods: A scoping review was initially conducted to narrow potential topics of exploration relating to CICI. From here, the authors chose certain factors determined non-modifiable. They used the PubMed database for the review. Using inclusion and exclusion criteria, the authors narrowed an initial 16,757 papers to 40 for review. The Cochrane Risk of Bias (ROB2) tool was used to assess risk of bias. Results: The studies show that older age, increased DNA methylation, decreased telomerase activity, genetics, changes in brain structure and volume, cancer type, increased cytokine factors, and decreased brain-derived neurotrophic factor (BDNF) serve as nonmodifiable predictive factors for CICI. Discussion: The purpose of this systematic review is to establish that certain NMFs—factors which cannot be changed—can be used to determine the risk of developing CICI. The authors urge researchers to use these factors to identify those that may be at greater risk for developing CICI and thus diagnose CICI during earlier stages. Funding: The authors received no funding for this systematic review. Registration:Protocol registered on PROSPERO Aug 2022. Registration number 42022349844.