A patient presenting with an adenocarcinoma of the rectum should be staged according the TNM staging system using different imaging modalities. Next to these classical clinical factors also circumferential margin involvement, size of the primary tumour and location of the primary tumour in relation to the anal sphincter are important factors in the treatment decision. The goals of preoperative treatment in rectal cancer are to reduce the risk of local relapse, to enable R0-resection and to preserve the anal sphincter in low-lying tumours. Radiotherapy can be administered either as a short course (5 fractions of 5 Gy, one fraction a day, overall treatment time of one week) or as a long course (25 fractions of 1.8 Gy, one fraction a day, overall treatment time of five weeks combined with chemotherapy eventually followed by an extra dose of radiation to the macroscopic tumor). In case of a short course of radiation total mesorectal excision (TME) is performed in the week following the end of radiation. In case of a long course of chemoradiation TME surgery is performed after an interval of 6 to 8 weeks. When immediate surgery is performed no tumour downstaging or downsizing can occur while after a long course of chemoradiation followed by a long interval before surgery up to 20% of patients have no tumour left in the resection specimen. Currently it is not known whether aiming for sphincter preservation after a good response to preoperative chemoradiation increases the risk of local recurrence. Learning Objectives: 1. To understand that the initial staging of rectal cancer determines the treatment approach (patient tailored treatment). 2. To understand the difference in approach between a short course of radiation and a long course of chemoradiation. 3. To become familiar with the concept of "the good, the bad and the ugly" in rectal cancer.