Prevalence of patient-reported and clinician-graded cognitive symptomatic adverse events in older patients with advanced cancer

Purpose: Cancer-related cognitive impairment is common in patients receiving cancer treatment but may be underdetected by clinician-graded adverse events (AEs) alone. Patient-reported outcomes and cognitive screening may improve identification of cognitive symptoms. Methods: We conducted a secondary analysis of the nationwide, multicenter GAP70+ trial of adults aged ≥70 years with advanced cancer starting systemic therapy. Cognitive symptoms were assessed longitudinally using patient-reported and clinician-graded cognitive AEs, and Mini-Cog screening at baseline, 4-6 weeks, 3 months, and 6 months. We examined prevalence, longitudinal trajectories, and associations with Mini-Cog impairment. Statistical significance was set at 2-sided P < .05. Results: Among 704 participants (mean age = 77.2 years; range = 70-96 years), patient-reported cognitive AEs were more prevalent than clinician-graded cognitive AEs at all time points: 19% vs 0.48% at 4-6 weeks, 18% vs 2.5% at 3 months, and 22% vs 0.44% at 6 months (all P < .001). Patient-reported cognitive AEs also fluctuated within patients over time. Impaired Mini-Cog was associated with higher patient-reported cognitive AEs at all post-baseline time points: 31% vs 15% at 4-6 weeks, 34% vs 14% at 3 months, and 49% vs 15% at 6 months (all P < .001). In contrast, associations with clinician-graded cognitive AEs were observed only at 3 months (P = .004) and 6 months (P = .04). Conclusions: Cognitive symptomatic AEs are common and often underdetected by clinician grading alone in older adults with advanced cancer. Combining patient-reported AEs with brief cognitive screening may improve detection during treatment. © The Author(s) 2026. Published by Oxford University Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.