How Long to Wait After Preoperative Radio(Chemo) Therapy to Perform Surgery

Preoperative radiotherapy or chemoradiotherapy (RT/CRT) is used in rectal cancer treatment to decrease the risk of a local recurrence in resectable tumours or to allow radical surgery in non-resectable tumours. In order not to increase the risk of complications after the surgery, surgery should be performed either before the acute radiation-induced toxicity has started, i.e. immediately after short-course RT (2–5 days), or after it has subsided 3–4 weeks after RT/CRT (i.e. 4–8 weeks after the last radiation fraction). Since regression of a rectal adenocarcinoma may take time and there presently is a wish to avoid (major) surgery in many patients, there is a growing interest in prolonging the interval from the RT/CRT to surgery to achieve maximal tumour regression. The pros and cons of delaying surgery are dependent upon the aim of the preoperative RT/CRT.