According to the current opinion, local excision in rectal cancer should be limited to selected T1N0 tumours. The investigators addressed the question whether preoperative radio(chemo)therapy can expand the use of this procedure for more advanced cancers. The rationale of preoperative radiotherapy is eradication of mesorectal subclinical disease. Besides, there is a correlation between radiosensitivity of rectal cancers and low cancer aggressiveness. For this reason, conversion to abdominal surgery is needed in patients with radioresistant tumour. The investigators aim to compare the short-course radiotherapy schedule with the chemoradiation in order to determine an optimal scheme. The study hypothesis is that the chemoradiation assures 25% more patients who do not require conversion to an open surgery. In addition, the aim is to asses safety and efficiency of preoperative radiotherapy and local excision for radiosensitive rectal cancer.