This is a prospective single-arm study investigating the benefit of on-couch adaptation for locally advanced rectal cancer patients prescribed with pre-operative sequential short-course radiotherapy (RT) followed by Oxaliplatin-combined chemotherapy (mFOLFOX(6) or CAPOX). On-couch adaptation, where the radiation dose is tailored to the anatomy of the patient at each radiotherapy session. Firstly, the study will investigate if on-couch adaptation result in less gastro-intestinal adverse events, secondly it will reveal if this possible reduction lead to more patients being able to fulfill all cycles of prescribed chemotherapy.
Diarrhea was the most frequently reported severe adverse event in the treatment regime of pre-operative sequential short-course radiotherapy followed by chemotherapy (so called total neo-adjuvant treatment).~This study therefore investigates the benefit of on-couch adaptation for locally advanced rectal cancer patients undergoing this treatment regime.