PURPOSE: To investigate the proportion of patients with lymphoma with persistent clinically relevant cognitive impairment, and its relation to treatment, fatigue, and psychological distress. METHODS: Patients with diffuse-large-B-cell-lymphoma (DLBCL), follicular-lymphoma (FL), and chronic-lymphocytic-leukemia (CLL)/small-lymphocytic-lymphoma (SLL), diagnosed between 2004-2010 or 2015-2019, were followed up to 8 years post-diagnosis. Sociodemographic and clinical data were obtained from the Netherlands Cancer Registry and the Population-based HAematological Registry for Observational Studies. The EORTC QLQ-C30 was used to assess cognitive functioning and fatigue, and the HADS to assess psychological distress. Individual growth curve models were performed. Results were compared with an age- and sex-matched normative population. RESULTS: A total of 924 patients were included (70% response rate). Persistent cognitive impairment was twice as high in patients (30%) compared to the normative population (15%). Additionally, 74% of patients reported co-occurring symptoms of persistent fatigue and/or psychological distress. Patients with FL (- 23 points, p <
0.001) and CLL/SLL (- 10 points, p <
0.05) reported clinically relevant deterioration of cognitive functioning, as did the normative population (FLnorm - 5 points, DLBCLnorm - 4 points, both p <
0.05). Younger age, higher fatigue, and/or psychological distress at inclusion were associated with worse cognitive functioning (all p's <
0.01). Treatment appeared less relevant. CONCLUSION: Almost one-third of patients with lymphoma report persistent cognitive impairment, remaining present up to 8 years post-diagnosis. Early onset and co-occurrence of symptoms highlight the need for clinicians to discuss symptoms with patients early. IMPLICATIONS FOR CANCER SURVIVORS: Early recognition of cognitive impairment could increase timely referral to suitable supportive care (i.e., lifestyle interventions) and reduce (long-term) symptom burden.