Accuracy of pre-operative examination in patients undergoing surgery, using trans-anal, endoscopic microsurgery

Background: Trans-anal endoscopic microsurgery (TEM) is an established, minimally invasive technique to treat rectal lesions up to 20 centimetres from the anal verge.

The technical limits when performing the operation are: the size of the pathologic lesion and the distance from the anal verge, with regard to the anatomical proportions of pelvis and rectum.

Malignant rectal lesions require a special approach and the depth of the rectal wall invasion is considered to be the most important factor in this procedure. The precision of pre-operative diagnostic screening is crucial in these cases. MRI or endo-rectal ultra-sound are usually used to evaluate rectal pathologic lesions before the operation. The results of the pre-operative biopsy are also considered in most cases.

Objective: The aim of the retrospective study was to determine the accuracy of routinely performed, staging investigations and their importance in indication algorithm.

Material and Methods: From November 2011 to December 2014, a total of 168 patients underwent pre-operative investigation and TEM in our institution. 72 were women and 95 men with an age range of 33 to 85 years (median: 64 years). The results of pre-operatively performed, endo-rectal ultrasound were compared with the invasion depth described by pathologists, as well as the results of definitive histopathological specimen with pre-operative biopsies.

Results: The accuracy of pre-operatively performed endo-rectal ultrasound (EUS) was deemed correct in 155 patients (93%). In 13 patients (7%) the depth of invasion differed between the EUS and the definitive histopathological conclusion. Only 57.4% of pre-operative biopsies conformed with definitive histopathological protocols.

Conclusions: Our results confirm that endo-rectal ultrasound is relevant in pre-operative examination before TEM procedures. However, results of pre-operative biopsies should not significantly influence the therapeutic algorithm.

No conflict of interest.