Staging rectal cancer: endoscopic ultrasound and pelvic MRI.

The success of pre-operative therapy over post-operative treatments means that a technique identifying prognostic factors pre-operatively is of potential benefit in modifying the intensity of pre-operative therapy according to risk of local or distant failure. Clinical trials incorporating robust and accurate assessment of prognostic factors and appropriate stratification of patients prior to therapy will enable objective comparison of treatment modalities and outcomes. Careful staging of rectal tumours results in selective pre-operative treatment strategies aimed at reducing local failure and distant failure in high risk patients.