The accuracy of endorectal ultrasound in staging rectal lesions in patients undergoing transanal endoscopic microsurgery

• Selection of patients for transanal endoscopic microsurgery (TEM) requires accurate preoperative staging.
• Fifty-three rectal cancer patients treated with TEM were evaluated by endorectal ultrasound.
• Of ultrasound results, 36.5% agreed with gold-standard histopathology findings.
• A Friedman test found ultrasound and histopathology stages differed significantly.
• Findings suggest endorectal ultrasound often overstages rectal tumors and should not preclude TEM.

BackgroundEndorectal ultrasound (ERUS) is used to preoperatively assess locoregional stage in patients with rectal neoplasms. This study evaluates the accuracy of ERUS in determining the T stage of rectal neoplasms treated by transanal endoscopic microsurgery (TEM).MethodsAll patients in the St Paul's Hospital TEM database were evaluated and excluded if they had been treated with neoadjuvant therapy. ERUS results were compared with gold-standard postoperative histopathology reports. Tumor height from anal verge was measured by ERUS and endoscopic techniques.ResultsFifty-three patients were eligible to participate in the study. A Friedman test demonstrated significant difference in the T stage between ERUS and the histopathology reports (P < .001). The tumor height measured by ERUS is significantly higher than the height measured by endoscopy (P < .05).ConclusionsThis study confirms that ERUS often overstages rectal neoplasms and suggests that ERUS findings should not preclude TEM in clinically appropriate patients.