Understanding and Tailored Treatment of Low Anterior Resection Syndrome

The goal of this observational study is to learn why some patients develop low anterior resection syndrome (LARS) after colorectal cancer treatment. The study also aims to identify different subtypes of LARS and understand which patients may respond to specific treatments. The main questions it aims to answer are: * What physiological and imaging changes are associated with LARS? * How do patients with LARS differ from patients without LARS after colorectal cancer surgery? * Are there measurable differences between LARS, patients treated with organ-preserving chemoradiotherapy, and patients with fecal incontinence? Participants will: * Complete advanced physiological and imaging assessments related to bowel function * Be compared with four control groups: * patients without LARS after colorectal cancer surgery * patients treated with organ-preserving chemoradiotherapy * patients with fecal incontinence and urge fecal incontinence * Take part in a single study visit where all measurements are performed