The use of rectal ultrasound for the correct diagnosis and treatment of rectal villous tumors.

Background: One of the difficulties associated with surgery for rectal villous tumors (RVT) is the finding of invasive adenocarcinoma after transanal excision (TAE) and the possible need for more radical procedures or adjuvant therapy. Improved preoperative evaluation may eliminate this dilemma. The aim of our study was to evaluate the role of transrectal ultrasound (TRUS) in establishing the correct diagnosis of RVT.

Methods: All patients with biopsy proven RVT, who were referred for TAE, underwent preoperative TRUS in addition to the routine evaluation. If invasion beyond the submucosa was suspected by TRUS, multiple biopsies were taken before any surgical intervention in order to exclude invasive cancer. If no invasion was noted, biopsies were avoided and a TAE was performed. The final pathology results were compared with both the preoperative diagnosis and TRUS results.

Results: Thirty-five patients (19 female, 16 male; mean age 67.5 years, range 36 to 88) were studied. The mean distance of the distal extent of the lesion above the anal verge was 5.8 cm (1.5 to 6). In 27 patients, the tumor was limited to the submucosa (uT0, uT1) on TRUS and, therefore, TAE was performed. In 26 of 27 patients (96%), pathology examination confirmed the presence of RVT without evidence of malignancy. One patient was found to have invasion of the muscularis propria and required postoperative radiation therapy. In 8 patients (23%), TRUS showed extension beyond the submucosa; 3 of these patients had uT2 lesions, 4 had uT3 tumors, and 1 had perirectal nodes. These 8 patients underwent repeated biopsies with the finding of invasive adenocarcinoma in 7. Two patients underwent abdominoperineal resection, 3 had a low anterior resection, and 3 had a TAE. Final pathology confirmed the preoperative diagnosis of invasive adenocarcinoma in 7 patients. In the 1 patient with a uT2 lesion and negative biopsies, the final diagnosis was RVT with no evidence of malignancy.

Conclusions: Preoperative TRUS provides an accurate diagnosis of RVT. In conjunction with TRUS-directed biopsies, directed management of these tumors could be achieved.