Implementation of a Tumor Response Assessment Program Integrating the Shared Medical Decision Into the Organ Preservation Strategy for Rectal Cancer Patients

The adoption of total mesorectal excision (TME) has standardized rectal cancer surgery and improved oncological outcomes. In locally advanced rectal cancer, neoadjuvant radio chemotherapy (NACRT) has further improved oncological benefit. Although these strategies result in good 5-year disease-free survival rates, they are associated with significant morbidity, in particular permanent long-term bowel, urinary and sexual dysfunction. In rectal cancer management, the main objective of organ preservation is to avoid or reduce morbidity and impact on quality of life after rectal resection, without compromising oncological outcomes. The aim of this project is to evaluate the efficacy of a defined response monitoring program, including a shared decision process, as a strategy for assessing tumor response in locally advanced rectal cancer after neoadjuvant therapy. This is a national, phase III, randomized, open-label, multicenter clinical trial comparing the tumor response monitoring program with shared decision-making, versus standard tumor response assessment in organ preservation strategies in rectal cancer.