Accuracy of transrectal ultrasonography in staging rectal tumors that are clinically eligible for transanal endoscopic microsurgery

Abstract

Purpose: Transanal endoscopic microsurgery (TEM) is performed in patients with premalignant or selected stage T1 rectal lesions. Transrectal ultrasonography (TRUS) is an important tool in the preoperative staging of rectal lesions to determine whether lesions are suitable for TEM or not. We analyze the accuracy of TRUS in distinguishing between rectal lesions requiring TEM or more radical excision.

Methods: From 2006 to 2008 thirty-five patients were included. All patients underwent TRUS. Following TRUS and/or additional imaging, patients underwent surgery. Preoperative TRUS staging was correlated to postoperative pathology findings.

Results: In 30 patients TRUS was diagnostic. Postoperative pathologic findings confirmed the preoperative TRUS findings in 29 patients; in 1 patient, a T3 staged tumor was an overstaged lesion biopsied as a tubulovillous adenoma. The accuracy level in the diagnostic TRUS group was 97% (29/30). In 5 patients TRUS was nondiagnostic; in 4 of these patients MRI was performed showing no tumor invasion in all 4 patients, confirmed by pathologic findings. Correct TRUS interpretation was possible in 86% (30/35). Overall accuracy of TRUS was 83% (29/35).

Conclusion: TRUS is accurate in distinguishing rectal lesions suitable for TEM from the lesions needing more radical surgery. If TRUS is nondiagnostic or the lesion is of high stage (>or=T2), MRI should be performed.