Transit endoscopic ultrasound of colorectal cancer using a 12 MHz catheterprobe

The objective of this study was to examine the accuracy of a 12 MHz ultraso und catheter probe in the pre-operative staging of colorectal cancer by ass essing the depth of tumour infiltration and involvement of pericolonic lymp h nodes. 159 patients with colorectal cancer who underwent ultrasound exami nation with a 12 MHz catheter probe were studied prospectively. The results of this imaging procedure were compared with the histological findings of the resected specimens. The accuracy of the 12 MHz ultrasound catheter prob e for depth of invasion (T category) was 85% (131/154) for all tumours, 87% (46/53) for pT1 tumours, 60% (9/15) for pT2 tumours, 89% (74/83) for pT3 t umours and 67% (2/3) for pT4 tumours. The accuracy for tumours of the rectu m and colon was 81% and 89%, respectively. The accuracy of the probe for no dal staging (N category) was 67% (76/114) overall. The sensitivity was 70% (33/47), the specificity 64% (43/67), the positive predictive value 58% (33 /57) and the negative predictive value 75% (43/57). Endoscopic ultrasound u sing a 12 MHz catheter probe accurately assessed tumour stage, although nod al staging remained suboptimal. This method may aid in the selection of tre atment for patients with colorectal cancer.