Systematic review of self-reported cognitive function in cancer patients following chemotherapy treatment

Cognitive symptoms are common in cancer patients, with up to 70% reporting cognitive symptoms following chemotherapy. These symptoms can have a major impact on how an individual functions in all aspects of their lives. This review evaluates self-reported cognitive function and its associations with neuropsychological tests and patient-reported outcomes in adult cancer patients who received chemotherapy treatment for a solid cancer. A search of multiple databases (Medline, Ovid at Nursing, PsycINFO, Allied and Complementary Medicine) from 1936 to 2017 was conducted, identifying 1563 unique articles, of which 101 met inclusion criteria. Of the 101 included studies, 48 (47%) were cross-sectional and 38 (38%) longitudinal in design, with 12 (12%) randomised controlled trials. A minority (26%) incorporated a healthy control arm in the study design, whilst the majority (79%) were in women with breast cancer. There was diversity in the assessment of self-reported cognitive symptoms. A total of 43 of 44 studies that sought an association between self-reported cognitive function and patient-reported outcomes found a moderate to strong association. Overall, 31 studies showed a lack of association between self-reported cognitive symptoms and neuropsychological results, whilst 14 studies reported a significant association between the two, but the association was often restricted to limited cognitive domains. The review found widespread heterogeneity in the assessment of self-reported cognitive symptoms and consistently absent or weak association with neuropsychological test scores. This research highlights the need for a standardised approach to measurement of self-reported cognitive symptoms in cancer patients.