The role of endoscopic ultrasound for loco-regional staging of rectal cancer.

Rectal cancer is projected to have the 10th highest incidence of cancer in the United States in 2009, with 40 870 estimated new cases this year. The prognosis for patients with rectal cancer is directly related to several factors, with the most important, based on current data, the extent of primary tumor invasion, the number of lymph nodes involved, involvement of the circumferential resection margin, and the presence of metastases. Contemporary therapy is dependent upon pre-surgical diagnostic imaging modalities, which influence the indication for neoadjuvant therapy and the decision process concerning the appropriate surgical approach. A comprehensive overview based on the currently available evidence of endoscopic ultrasound imaging in the loco-regional assessment of primary de novo rectal cancer evaluation following neoadjuvant therapy and post operative disease surveillance is presented. Relevant ano-rectal anatomy, staging systems for rectal cancer and alternative radiological staging strategies are also presented.