Preoperative radiotherapy is standard procedure in rectal cancer treatment protocols. Experience and analysis of clinical and laboratory features of the results of this procedure have established that the response to radiotherapy, in order to reduce the volume of tumor and adenopathies of stations I and II is highly variable, from complete disappearance of the tumor mass, to the lack of response. The response to radiotherapy in conjunction with pathological and immunohistochemical data could allow assessment of prognosis in the rectal cancer. For this purpose we have proposed conducting a clinical trial to examine the tumor grading, immunohistochemical markers, and possible genetic changes that allow assessment of the degree of post-radic regression and the postterapeutic prognosis. Based on these criteria would be possible to establish a group of regression in which the patient stands still from the pretherapeutic phase. In this way the type of the presurgical radiation would shade, sometimes this standard being made ineffective. We come with a lot preliminary statistics, with the value of working hypothesis.