Radiotherapy for rectal cancer: Short course versus long course – When and how

Prior to the introduction of improved surgical techniques such as total mesorectal excision, local recurrence rates after resection were unacceptably high with surgery alone. Phase III trials were designed to determine the benefit of the addition of radiotherapy to radical surgery, and these have reported significant reductions in local recurrence. Two different strategies were evaluated in the preoperative setting. Initially in Scandinavia the approach of a hypo-fractionated 1-week course of radiotherapy performed prior to radical surgery was evaluated in a series of phase III trials. In contrast, the strategy of integrating fluoropyrimidine chemotherapy with long-course fractionated radiotherapy in the postoperative setting was then evaluated preoperatively. Two key trials determined that the addition of fluoropyrimidine to neoadjuvant radiotherapy compared with radiotherapy alone significantly reduced the risk of local recurrence. Following the increasing use of total mesorectal excision and the associated lower rates of local recurrence, in the Netherlands and in the United Kingdom (UK) two phase III trials were conducted. The Dutch TME and MRC CR07 trials showed a reduction in local recurrence from the addition of short-course preoperative radiotherapy but without any impact on overall survival. The two strategies (short-course and long-course treatment) have developed in parallel. This leads to a number of questions: