Preoperative staging of colorectal carcinoma

Carcinoma of the colorectum is one of the most frequent neoplasias, with an incidence of 40 in 1 00 000. For the effective use of new, differentiated, less invasive treatment options, exact preoperative staging of the tumor i s essential. The introduction of endosonography in rectal tumor staging all ows for exact differentiation of the rectal wall layers and thus of tumor s tages 1-3 with median accuracy of 89%. Magnetic resonance imaging of the re ctum, especially in double-contrast technique, can also be employed in high and stenosing tumors and leads to an average accuracy of 85% for the stage s 1-4. Computed tomography is the method of choice in screening for metasta ses. In lymph node staging, a II modalities show only moderate accuracy aro und 75%.