Magnetic resonance imaging of patient 3. Magnetic resonance image of patient 3 with squamous cell carcinoma of the rectum (A, B). The tumor was diagnosed as being at clinical stage T4b N2b M0. The patient received chemoradiation therapy with S-1 (C, D), and then, a posterior pelvic exenteration with advancement flap reconstruction was performed as salvage therapy. Pathological findings revealed no tumor cells in either the resected specimen or the lymph nodes (i.e., a pathological complete response).