A team from Minneapolis, Minnesota, USA, evaluated the accuracy of endorectal ultrasonography in preoperative staging of rectal tumors.
Some 1184 patients with rectal adenocarcinoma or villous adenoma underwent endorectal ultrasonography evaluation at a single institution during a 10-year period.
The researchers compared the endorectal ultrasonography staging with the pathology findings based on the surgical specimens in 545 patients who had surgery (307 by transanal excision, 238 by radical proctectomy) without adjuvant preoperative chemoradiation.
Overall accuracy in assessing the level of rectal wall invasion was 69%, with 18% of the tumors overstaged and 13% understaged.
It was found that accuracy depended on the tumor stage and on the ultrasonographer.
| Overall accuracy of endorectal ultrasonography in assessing level of rectal wall invasion was 69%.
| Diseases of the Colon & Rectum |
Overall accuracy in assessing nodal involvement in the 238 patients treated with radical surgery was 64%, with 25% overstaged and 11% understaged.
Dr Julio Garcia-Aguilar, of the University of Minnesota in Minneapolis, said on behalf of fellow authors, "The accuracy of endorectal ultrasonography in assessing the depth of tumor invasion, particularly for early cancers, is lower than previously reported.
"The technique is more precise in distinguishing between benign tumors and invasive cancers, and between tumors localized to the rectal wall and tumors with transmural invasion."
"Differences in image interpretation may in part explain discrepancies in accuracy between studies," it was concluded.