Preoperative staging of rectal cancer.

Rectal cancer is one of the most frequent neoplasias, with an incidence of 40 in 100,000. For the effective use of new, differentiated treatment options, exact preoperative tumour staging is essential. The tumour stage determines whether radiation or chemotherapy should be used in addition to surgery. Endosonography allows exact differentiation of the rectal wall layers and thus of tumour stages 1-3 with median accuracy of 89%. Magnetic resonance imaging (MRI) can be employed in high and stenosing tumours and leads to an average accuracy of 85%. In recent studies, it has been shown that MRI is a valuable tool to identify the mesorectal fascia. This is a very important feature concerning the resectability and the risk of recurrence. Both, Endosonograpy and MRI plays an important and complimentary role in staging rectal cancer.