Preoperative staging of colorectal cancer by a 15 MHz ultrasound miniprobe.

Abstract

Our objective was to examine the accuracy of a 15 MHz ultrasound miniprobe in the pre-operative staging of colorectal cancer by assessing the depth of tumor infiltration and involvement of pericolonic lymph nodes. Thirty-three patients with colorectal cancer who underwent ultrasonography with a miniprobe were studied prospectively. The results of this imaging were compared with the histologic findings of the resected specimens. The accuracy of the miniprobe for depth of invasion (T category) was 82% (27 of 33) for all tumors, 76% (13 of 17) in pT1 cases, and 88% (14 of 16) in pT2 to pT4 cases. The accuracy of the miniprobe for nodal staging (N category) was 87% (26 of 30) overall. The sensitivity was 63% (5 of 8), the specificity was 95% (21 of 22), the positive predictive value was 83% (5 of 6), and the negative predictive value was 88% (21 of 24). The miniprobe is an accurate method for the preoperative TN staging of colorectal cancer. We recommend its preoperative use because the results may influence the surgical approach.