Individualized trajectories in post-radiotherapy neurocognitive functioning of patients with brain metastases

The increasing incidence of brain metastases (BMs) and improved survival rates underscore the necessity to investigate the effects of treatments on individuals. The aim of this study was to evaluate the individual trajectories of subjective and objective cognitive performance after radiotherapy in patients with BMs. The study population consisted of adult patients with BMs referred for radiotherapy. A semi-structured interview and comprehensive neurocognitive assessment (NCA) were used to assess both subjective and objective cognitive performance before, 3 months and ≥11 months after radiotherapy. Reliable change indices were used to identify individual, clinically meaningful changes. Thirty-six patients completed the 3-month follow-up, and 14 patients completed the ≥11-months follow-up. Depending on the domain, subjective cognitive decline was reported by 11-22% of patients. In total, 50% of patients reported subjective decline on at least one cognitive domain. Intracranial progression 3 months post-radiotherapy was a risk-factor for self-reported deterioration (p=.031). Objective changes were observed across all domains, with a particular vulnerability for decline in memory at 3 months post-radiotherapy. The majority of patients (81%) experienced both a deterioration as well as improvement (e.g. mixed response) in objective cognitive functioning. Results were similar for the long-term follow-up (3-≥11 months). No risk factors for objective cognitive change 3 months post-radiotherapy were identified. Our study revealed that the majority of patients with BMs will show a mixed cognitive response following radiotherapy, reflecting the complex impact. This underscores the importance of patient-tailored NCAs three months post-radiotherapy to guide optimal rehabilitation strategies.