Comparative evaluation of endoscopy and endoscopic ultrasonography in localization of anorectal tumours

Introduction: Comparative evaluation of endoscopy and anorectal ultrasonography (US) was performed for 24 patients suffering from anorectal tumours. According to our experiences these two types of examinations have showed the localisation and extension of the tumours differently. The purpose of our study was to analyse the reasons for these differences.

Patients and methods: Anorectal US was made for 24 patients with rectal tumour that had been verified by endoscopy and in most cases by histopathology. The equipment used for anorectal US and endoscopy was B-K Medical Hawk EXL and Olympus CF100 respectively. 6 women and 18 men between 31 and 83 years of age were examined. For 19 patients rectal US and for 5 patients both rectal and anal US have been performed.

Results: Histopathologi diagnosis: 17 adenocarcinoma, 3 anaplastic carcinoma, 1 gelatinous carcinoma, 3 villous adenoma (two of them with moderate, one with severe dysplsia). The distal border of the tumour measured from the anal ring was determined. According to our experiences the distance showed by endoscopy was greater in 14 cases, equal in 4 cases and less in 6 cases comparing to the US measurements. There were differences in the size of the tumour too: US showed the tumour greater than endoscopy in 12 cases, the size was less by US in 3 cases. In 4 cases the size was the same by endoscopy and by US and in 5 cases the size couldn't be correctly measured due to stenosis. In our opinion the main reason for the differences in the subjective character of the endoscopic measurements. The magnified picture on the screen of the endoscope doesn't allow precise measurements. An other reason is that in contrary to endoscopy US is able to detect precisely lesions that don't reach the mucous surface. It's more difficult to determine the loction (height) of the anal sphyncter by endoscopy while US can show this precisely.

Conclusion: According to our experiences US was better in establishing the correct size and location of anorectal tumours, than traditional endoscopy. For this reason US is preferable in the decision making.