Background: Surgical resection of the rectum still remains the most important treatment of rectal cancer. However, surgery alone is not able to improve the outcome of the therapy more than currently reported. Recently, the role of an adjuvant or a neoadjuvant therapy together with total mesorectal excision (TME) has been emphasised. The purpose of this study was to estimate the effect of preoperative radiotherapy on the local progression of rectal cancer using transrectal ultrasound (TUS) and to evaluate the usefulness of TUS in the assessment of changes and advancement of rectal cancer after hyperfractionated preoperative radiotherapy (PR).
Material and methods: The study was performed in a group of 58 patients with proven rectal cancer. 30 patients underwent preoperative radiotherapy and 28 patients (control group) were treated using surgery alone. In all the patients TUS was done - the infiltration of the wall of the rectum and lymph node involvement were examined. The patients were irradiated with 20 MV. The total dose was 42 Gy in 28 fractions. Surgical resection was performed from 1 to 7 days after the completion of PR. The second TUS was performed just before the operation to estimate the influence of hyperfractionated preoperative radiotherapy on the local regression of rectal cancer. The results of the second TUS underwent pathological verification. The overall accuracy of the TUS in our study was 89.2% in the estimation of the depth of the rectum wall infiltration and 75.0 % in the estimation of the lymph node involvement.
Results: According to TUS the local tumour regression was observed in 10 out of 30 cases (30.0%). In 7 patients the regression was confirmed by a second transrectal ultrasound examination. In 2 patients with recurrent rectal cancer transrectal ultrasound did not confirm the regression after preoperative radiotherapy.
Conclusions: The hyperfractionated preoperative radiotherapy, with a short interval between the end of preoperative radiotherapy and the operation, causes the regression of local advancement of rectal cancer. Transrectal ultrasound examination is useful in the assessment of changes in rectal cancer advancement after hyperfractionated preoperative radiotherapy.