Prospective memory in breast cancer survivors treated with endocrine therapy: findings from an ecological virtual reality task.

OBJECTIVE: Cognitive effects of endocrine therapy (ET) in breast cancer are often subtle and may escape detection by standard neuropsychological assessments. Prospective memory (PM)-the ability to carry out intended actions-is particularly sensitive to mild cognitive changes, and crucial for autonomy and treatment adherence. This study examined the impact of ET, administered without chemotherapy, on PM using a virtual reality (VR)-based paradigm. METHOD: Thirty-eight postmenopausal breast cancer survivors treated with ET (ET+) or without ET (ET-), and 21 healthy controls were evaluated. To isolate the cognitive effects of ET, none of the patients had received chemotherapy. Participants completed standardized neuropsychological tests, self-report questionnaires, and a VR-based PM task assessing recall of event-based (EB) and time-based (TB) intentions after short (10-min) and long (10 h) delays. RESULTS: Despite preserved performance on standard neuropsychological measures, ET+ patients showed significantly lower PM performance than ET- patients, specifically for TB intentions after the short delay (p.adj = .002). The prospective component of these TB intentions was particularly less frequently retrieved (p.adj = .014), despite preserved storage. CONCLUSIONS: This study provides preliminary evidence suggesting that ET, independent of chemotherapy-related neurotoxicity, may be associated with alterations in PM. The pattern of PM performance in ET+ patients suggests a disruption in self-initiated retrieval processes during early consolidation, when memory traces remain labile and vulnerable to interference. The use of an immersive VR-based PM paradigm revealed subtle cognitive changes not captured by conventional assessments, underscoring the clinical value of ecologically valid tools.