Clinical value of radial endorectal ultrasound in the assessment of preoperative staging of rectal carcinoma

Abstract

To evaluate the clinical value of radial endorectal ultrasound (ERUS) in the assessment of preoperative staging of rectal carcinoma. One hundred and ten patients with rectal cancer underwent preoperative endorectal ultrasound (ERUS) examination in our hospital from February 2010 to September 2011. ERUS was performed using a Hitachi 900, Hitachi HI Vision Preirus US scanner, with a 5 - 10 MHz rigid rotating radial transducer and a focal length of 2 - 5 cm. The size, shape, echo pattern, infiltration depth, degree of circumferential involvement, extra-rectal invasion of the lesions and lymph node involvement were observed. The results of ERUS staging were compared with histopathological findings of the surgical specimens. The accuracy of ERUS for T staging was 91.4%. The accuracy of ERUS in diagnosing stage T1, T2, T3, T4 cancers was 92.7%, 88.2%, 88.2% and 96.4%, respectively. The sensitivity of ERUS in diagnosing stage T1, T2, T3, T4 cancers was 92.3%, 72.7%, 85.4% and 71.4%, respectively. The specificity of ERUS in diagnosing stage T1, T2, T3, T4 cancer was 92.9%, 92.0%, 90.3% and 100.0%, respectively. Comparing the consistency of preoperative T-staging and postoperative pathological results, the Kappa value was 0.75, with a considerable consistency. The sensitivity, specificity, and accuracy of ERUS in the assessment of lymph node metastasis were 74.2%, 89.9% and 85.5%, respectively. Comparing the consistency of preoperative N-staging and postoperative pathological results, the Kappa value was 0.64, with a considerable consistency. ERUS is a practical and accurate tool in assessment of preoperative staging of rectal tumors in regard to tumor invasion depth (T) and regional lymph node status (N), with advantages of simple operation, less pain, and high accuracy.