Quantifying chemotherapy-induced cognitive impairment in gastrointestinal cancer patients: A scoping review of methodological concerns in the literature.

Purpose: Chemotherapy is one of the common treatments in cancer management. However, chemotherapy-induced cognitive impairment (CICI) is one notable side effect that can greatly impact a patient's quality of life. Literature on CICI in gastrointestinal (GI) cancers are few and inconsistent. This review aims to identify the methodological differences in such studies.

Methods: A systematic search was performed in four electronic databases. All peer-reviewed primary literature published in English that evaluated cognitive-related functioning scores related to chemotherapy in GI cancer patients were included. Information about each study such as CICI findings, study limitations, methodology, and sample characteristics was extracted and synthesized.

Results: A total of 19 studies were included. Evidence of CICI was found in 50.0% (8 of 16) and 62.5% (5 of 8) studies that used objective and subjective measures, respectively. Methodological differences such as groups used for comparison, instruments used, and assessment from the length of time since chemotherapy were highlighted between studies that did and did not find evidence of CICI.

Conclusions: This review suggests that the mixed findings can be attributed to the heterogeneous methodologies adopted in the evaluation of CICI in this field.

Implications for cancer survivors: Further studies are necessary to establish the presence and chronicity of CICI, and in which groups of patients to facilitate targeted interventions and treatments.