153TiP Effects of resistance vs aerobic training on Ki-67 and other health-related biomarkers: The neo-program, a randomized controlled trial on breast cancer patients undergoing neoadjuvant treatment

Physical exercise has been considered one of the relevant factors in breast cancer (BC) prevention and recovery. During cancer treatment, physical exercise has also been proven to help in coping with the side effects of chemotherapy and to shorten recovery following BC surgery. Moreover, some preliminary data showed that exercise can impact tumor growth and biology. However, the evidence describing the impact of exercise on cancer during neoadjuvant treatment remains scarce. Therefore, it is paramount to assess the impact of adding exercise during neoadjuvant therapy (NAT) on tumor characteristics and to elucidate the physical and psychological impact on patients, namely on their quality of life. We aim to examine and compare the effects of two different exercise protocols (aerobic and resistance) against a relaxation control group on Ki-67 changes, as the primary outcome, in BC patients undergoing NAT. We hypothesize that both exercise groups will experience a more marked decrease in Ki-67 levels when compared to the control group. Secondary outcomes will include changes in body composition, physical fitness, quality of life, sleep efficiency and fatigue as well as dynamic changes in inflammatory and immune biomarkers, from baseline to end of NAT. A total of 132 histologically confirmed hormone-positive/HER2-negative (stage 0-III) patients with BC (≥ 18 years) scheduled for NAT (66 chemotherapy; 66 endocrine therapy) will be recruited and randomized to one of 3 groups: 1) aerobic training (moderate continuous cycling); 2) resistance training (3x 8-12 repetitions of 8 strength exercises; up to a maximum of 70%-maximum repetition); 3) control. The Ki-67 expression will be measured on the initial tumor biopsy and surgical specimen. Considering its multidisciplinary and translational nature, this trial will allow us to draw more robust conclusions on the impact of exercise on BC patients, laying a framework for future exercise-based interventions in cancer patients during NAT. NCT05297773. Champalimaud Foundation. Has not received any funding.