Abstract
Preoperative radiotherapy (RT) or chemoradiotherapy (CRT) is often required before rectal cancer surgery to obtain low local recurrence rates or, in locally advanced tumours, to radically remove the tumour. RT/CRT in tumours responding completely can allow an organ-preserving strategy. The time from the end of the RT/CRT to surgery or to the decision not to operate has been prolonged during recent years. After a brief review of the literature, the relevance of the time interval to surgery is discussed depending upon the indication for RT/CRT. In intermediate rectal cancers, where the aim is to decrease local recurrence rates without any need for down-sizing/-staging, short-course RT with immediate surgery is appropriate. In elderly patients at risk for surgical complications, surgery could be delayed 5-8 weeks. If CRT is used, surgery should be performed when the acute radiation reaction has subsided or after 5-6 weeks. In locally advanced tumours, where CRT is indicated, the optimal delay is 6-8 weeks. In patients not tolerating CRT, short-course RT with a 6-8-week delay is an alternative. If organ preservation is a goal, a first evaluation should preferably be carried out after about 6 weeks, with planned surgery for week 8 if the response is inadequate. In case the response is good, a new evaluation should be carried out after about 12 weeks, with a decision to start a 'watch-and-wait' programme or operate. Chemotherapy in the waiting period is an interesting option, and has been the subject of recent trials with promising results.