Is there a relationship between objectively measured cognitive changes in patients with solid tumours undergoing chemotherapy treatment and their health‐related quality of life outcomes? A systematic review

BACKGROUND: This systematic review examines whether there is a relationship between objective measures of chemotherapy-related cognitive impairment in patients with solid cancer tumours and health-related quality of life (HRQoL). METHODS: Multiple online databases were searched (including Ovid MEDLINE, EMBASE, PsycINFO, PsycARTICLES, CINAHL, PubMed, and Web of Science) to identify articles published between 1980 and 2016 examining the extent of chemotherapy-related cognitive deficit and its relationship with HRQoL in cancer patients. Of 2769 potentially relevant articles, 17 studies met the inclusion criteria for the current review. RESULTS: Evidence for the presence of cognitive impairment in patients treated with chemotherapy was found in 15 of the 17 studies. Of the 15 studies finding some sort of cognitive impairment, 12 were in female breast cancer patients, 2 in bowel cancer, and 1 each in ovarian and lung cancer. Three of the 15 studies found a significant relationship between various objectively measured cognitively impaired domains and specific HRQoL outcomes. There was, however, only limited testing of the relationships between quantifiable cognitive dysfunction and HRQoL domains. CONCLUSIONS: This review suggests that in patients with solid tumours, where there is a relationship between chemotherapy treatment and cognitive impairment, the type and level of cognitive decline does not consistently appear to affect such patients' HRQoL. This could be partly explained by variations in study design, measures used, definitions of cognitive impairment, varying measurement time frames, small sample sizes, and differences in disease severity and type of treatment regimes.