Neuromorphological effects of simultaneous exercise during neo-/adjuvant chemotherapy in breast cancer patients: The Exercise Cancer and Cognition (ECCO) study.

544 Background: Cancer-Related Cognitive Impairment (CRCI) is commonly experienced by breast cancer patients, often linked to chemotherapy. It manifests as deficits in learning, memory, reaction time, and concentration, with the hippocampus—a critical region for cognitive and affective functions—playing a central role. The hippocampus retains neurogenesis potential throughout life, with physical exercise shown to enhance hippocampal volume and memory function. High-intensity exercise appears to have superior cognitive benefits compared to moderate aerobic activity. The ECCO study aimed to assess the neuropsychological and brain morphological effects of high-intensity interval training (HIIT) in breast cancer patients, focusing here on imaging data subanalysis. Methods: The ECCO-study was designed as monocentric two-armed 1:1 randomized controlled trial (RCT), including a 12-month intervention group and a control group. Patients in the intervention group were instructed to perform strength- and low-intensity endurance training at least once a week at home according to the American College of Sports Medicine (ACSM) recommendations and to complete a supervised high-intensity interval training (HIIT) once a week at our health center. Patients in the control group were advised physical activity recommendations according to the World Health Organsiation (WHO). Participants randomized to the control arm received usual care and physical activity recommendations have been given according to usual standards. The volume measurements of the brain were performed with an automatic segmentation tool FreeSurfer version 7.4. The FreeSurfer algorithm performs an automatic segmentation of subcortical volumes and reconstructs the cortex after the elimination of non-brain tissue. Results: MRI data were available at baseline and after 12 months for a total of 67 patients diagnosed with breast cancer. Randomized into an intervention arm (n = 35) and control arm (n = 32). The groups were comparable in all demographic factors such as age, BMI and VO2max. There were no statistically significant changes (p < 0.05) in the volumes between the baseline measurement and the 12-months-follow-up measurement. Other brain areas also showed no significant (p < 0.05) alterations between baseline and follow-up. No differences were found in the volume change between the exercise group and the control group. Conclusions: This analysis of the ECCO study revealed that there were no significant changes in hippocampal volume or in the more precise categorization into its subfields in either the intervention or control group of breast cancer patients. Contrary to hypotheses suggested in the literature, it was shown that breast cancer therapy does not lead to morphological changes in the hippocampus, indicating that CRCI is not based on morphological damage. Clinical trial information: NCT04789187 .