Role of endorectal ultrasonography in preoperative staging of rectal cancer

Abstract

olorectal cancer is the fourth most common type of cancer worldwide yet there continues to be controversy and confusion regarding the best methods and techniques for its diagnosis and management. The treatment of rectal carcinoma is mainly determined by its local extension. Preoperative staging of rectal carcinoma can be assessed by different methods: digital rectal examination, transrectal ultrasound, computed tomography, and magnetic resonance imaging. The first articles about endorectal ultrasonography (ERUS) and its application in diagnostics of anorectal diseases date since 1956. Its use in clinical practice was limited mostly because of the bad technical characteristics of probes (1,2). Over the past several years, the tremendous improvements in endorectal and endoanal ultrasonography allowed a much more accurate evaluation of both benign and malignant anorectal diseases and what is more important staging of rectal tumors and surrounding lymph nodes. Moreover, ERUS provides visualization and diagnostic of prostate gland, seminal vesicles, vagina, urinary bladder and rectouterine (Douglas) space (1-4). Usually, 7.5-MHz, 10-MHz and 12-MHz radial scanning transducers are used. These transducers provide transverse 360° scans in the longitudinal axis of the rectum. The patient is in the left lateral decubitus position. The echoendoscope is inserted up to 25 cm from the anal verge, to the location of the root of the inferior mesenteric artery. For acoustic contact, the rectal lumen is filled with latex balloon inflated with degassed water. The examination is complete when the entire tumor, rectum, mesorectum and surrounding structures are visualized thor