[Selection of patients with rectal tumors for local excision based on preoperative diagnosis. Results of a consecutive evaluation study of 552 patients].

INTRODUCTION: The aim of our study was to evaluate the accuracy of clinical staging (CS), biopsies, and endoluminal ultrasonic examination (EUS) in preoperative staging of rectal tumors treated with transanal local excision. This local excision is an adequate procedure for benign rectal polyps and low-risk T1 carcinoma. PATIENTS AND METHODS: The study included 552 patients with rectal adenocarcinoma, villous adenoma, or tumors with other histologic characteristics who underwent a transanal excision (transanal endoscopic microsurgery n=513 or transanal excision n=39). We compared the results of CS, biopsies, and EUS with postoperative pathology findings.
RESULTS: Preoperative histological diagnosis of the rectal carcinoma depended on tumor size (52% in cancers <3 cm, 25% in cancers >3 cm; p=0.001) and was correct in 56% of cases. Transanal ultrasonography (uT0/1) had superior sensitivity (95% vs 78%) and a higher positive predictive value (93% vs 85%) than clinical staging (CS I) in detecting adenoma or T1 rectal carcinoma, whereas specificity was similar in both (62% vs 58%). In patients in whom preoperative histological analysis revealed adenomas, transanal ultrasonography was accurate (uT0/1) for the postoperatively assessed adenoma pT1 in 97%, whereas diagnosis (uT0/1) was correct in only 71% of cases in which preoperative histological analyses showed rectal carcinomas.
CONCLUSIONS: In patients with rectal tumors, preoperative staging with transanal ultrasonography and biopsy is essential for the indication and allows selection of patients for transanal local excision.