P.023 Review of imaging changes, cognitive decline, and dementia risk in cancer survivors after chemotherapy

Background: Cancer survival rates in Canada have been improving, leading to a steady increase in the number of survivors entering the typical ages of dementia onset. Yet, some cancer treatments (e.g. chemotherapy) are neurotoxic and adversely affect normal brain functioning. We conducted a review to examine changes observed in brain imaging and cognitive measures in survivorship, and long-term risk of dementia among cancer survivors. Methods: 91 Primary studies were selected from PubMed. Inclusion criteria were studies investigating the changes in brain imaging, cognition, and future dementia risk among adult survivors who received chemotherapy. Study quality was assessed based on 1) prospective, controlled design, 2) sample size, and 3) validated imaging and cognitive metrics. Results: Imaging studies identified MRI-based structural grey and white matter changes and functional network changes among survivors. Cognitive studies reported heterogeneous impairments in attention, memory, and executive function. In studies that examined dementia risk among cancer survivors, 67% reported lower risk of dementia, while 33% reported no association or a higher risk. Conclusions: While short-term cognitive impairment with associated changes on brain imaging is widely reported, findings concerning future or long-term cognitive impairment are mixed. Studies are warranted to identify potential connections between short-term and long-term cognitive function after cancer treatment.