Primary Rectal Cancer and Local Invasion

Rectal cancer has a hypoechoic apearance on the sonogram, and, as it invades deeper through the rectal wall, the normal sonographic anatomy is disrupted. The accuracy of endosonography for diagnosing rectal cancers is given for some authors in Table 6.1. By comparing the changes caused by a tumour with the normal sonogram the depth of tumour invasion can be assessed. So that this invasion can be reported in a standardised way it has been compared to histopathological staging methods. The Dukes classification has the disadvantage that a Dukes B cancer may also be a tumour invading the mesorectum early or one with wide local invasion.