Comparison of hydrocolonic sonograpy accuracy in preoperative staging between colon and rectal cancer

To compare the accuracy of hydrocolonic sonography (HUS) in determining the depth of invasion (T stage) in colon and rectal cancer.

A total of 1 000-2 000 mL of saline was instilled per rectum using a system for barium enemas, and then ultrasonography was conducted by a SSA-270A (Toshiba Co, Japan) sonolayer unit with a 3.75 MHz for 17 patients with colon cancer and 13 patients with rectal cancer before operation. After operation, T stage in HUS was compared with postoperative histological findings.

Overall, the accuracy of T stage was 70%. It was 88% in colon cancer and 46% in rectal cancer. In evaluating nodal state, the accuracy of HUS was low in both colon (71%) and rectal cancers (46%) compared with conventional CT or MRI. The overall accuracy of N staging was 60%.

HUS is valuable to evaluate the depth of invasion in colon cancer, but is less valuable in rectal cancer. Because HUS is low-cost, noninvasive, and readily available at any place, this technique seems to be useful to determine the preoperative staging in colon cancer, but not in rectal cancer.