The Medical Research Council CR07/National Cancer Institute of Canada Clinical Trials Group C016 (MRC CR07/NCIC CTG C016) trial showed that, in patients with operable rectal cancer, short-course preoperative radiotherapy (PRE) reduced the rate of local recurrence compared with surgery followed by selective postoperative chemoradiotherapy for patients with a positive circumferential resection margin. However, the advantages of giving PRE to all patients needs to be balanced against any negative impact on patients' quality of life.