Multimodal Prehabilitation Program That Combines Physical Exercise, Psychological Intervention and Nutritional Support to Improve the Response to Neoadjuvant Chemoterhapy in Early Breast Cancer Patients

Breast cancer (BC) is the most common neoplasm worldwide and the leading cause of death among women. Neoadjuvant chemotherapy (NACT) is currently one of the main therapeutic pillars. The pathological response after NACT has demonstrated prognostic value in BC, being also a determinant factor for posterior treatments. In recent years, research has increasingly focused on the impact of lifestyle changes on BC, such as physical exercise, diet, and psychological interventions. These actions are part of what is known as prehabilitation, defined as the set of strategies applied prior to surgery to optimize the physical and emotional condition of patients before the surgical intervention. The individual application of these strategies in BC patients has shown improved oncological outcomes, with positive effects on quality of life and tolerance to medical treatments. Furthermore, evidence suggests that these interventions may favorably modulate the tumor microenvironment by reducing intratumoral hypoxia, enhancing antitumor immune responses, and modulating systemic pro-inflammatory states. Despite the demonstrated benefits of prehabilitation in multiple medical and surgical fields, there is limited evidence regarding its impact on systemic treatment outcomes in BC patients. There is also a lack of solid evidence evaluating the role of multimodal prehabilitation (combining different prehabilitation strategies) in BC, as well as its effect on treatment response and tolerance. The current study proposes the application of a multimodal prehabilitation program during the NACT window, based on structured physical exercise, psychological therapy (mindfulness or anxiety-control techniques), and nutritional counseling in BC patients, as a strategy to enhance treatment response through changes in the tumor microenvironment. Additionally, it will be assessed whether the intervention improves treatment tolerance and postoperative recovery, among others. The study consists of a randomized, single-blind, controlled clinical trial with two parallel groups that will include 214 women diagnosed with non-metastatic breast cancer, eligible for NACT, and awaiting surgery at our center. Participants will be randomized into two parallel groups in a 1:1 ratio (control and intervention group, including 107 women each). A basal evaluation will be performed in all patients before starting NACT, reporting their physical, nutritional and psychological status, as well as a tumor microenvironment study in the diagnostic biopsy sample. All patients will undergo 4-6 months of NACT, the control group with standard clinical management and the intervention group following the multimodal prehabilitation program. After NACT, the physical, nutritional and psychological status of all patients will be re-evaluated. Patients will undergo surgery according to their disease and the pathological response to the treatment will be assessed. The primary outcome will be the pathological response after NACT in both groups, assessed through the Residual Cancer Burden (RCB) index. Secondary outcomes will include NACT tolerance, quality of life, psychological and nutritional status, postoperative recovery, tumor microenvironment changes and patients' physical condition. The group of BC patients undergoing the multimodal prehabilitation program during NACT is expected to achieve better response rates (RCB 0 and I) than the control group. Furthermore, the multimodal intervention is anticipated to promote quantitative and/or qualitative changes in the tumor microenvironment, improve NACT tolerance, enhance quality of life, and optimize postoperative recovery and the patients' physical, psychological, and nutritional status.