The accuracy of endorectal ultrasonography in rectal cancer staging

The incidence of rectal cancer in the European Union is about 35% of the total colorectal cancer incidence. Staging rectal cancer is important for planning treatment. It is essential for the management of rectal cancer to have adequate preoperative imaging, because accurate staging can influence the therapeutic strategy, type of resection, and candidacy for neoadjuvant therapy. The aim of this work is to evaluate the accuracy of endorectal ultrasound (ERUS) in rectal cancer staging.

A retrospective study was performed to assess the accuracy of ERUS by analyzing patients discharged from Regional Institute of Gastroenterology and Hepatology (IRGH) Cluj-Napoca, Romania, diagnosed with rectal cancer between 01 January 2011 and 31 December 2013. Patients who were preoperatively staged by other imaging methods and those who had ERUS performed in another service were excluded from the analysis. As inclusion criteria remained ERUS performed for patients with rectal cancer in IRGH Cluj-Napoca where they were also operated. We analyzed preoperative T stage obtained by ERUS and it was compared with the histopathology findings.

The number of patients discharged with a diagnosis of rectal cancer were 200 (operated - 157) in 2011, 193 (operated - 151) in 2012, and 198 (operated - 142) in 2013. We analyzed a total of 51 cases diagnosed with rectal cancer who performed ERUS in IRGH Cluj-Napoca. The results according to the T stage obtained by ERUS and histopathology test were: Under-stage T2= 25.0%, T3=7.9% of cases;Over-stage T2=25.0%, T3=31.6% and T4=60.0% of cases.Less than 20% of patients underwent preoperative radio-chemotherapy.

ERUS is a method of staging rectal cancer which is human dependent. ERUS is less accurate for T staging of stenotic tumours, but the accuracy may still be within acceptable limits. Surgeons use ERUS to adopt a treatment protocol, knowing the risk of under-staging and over-staging of this method. The accuracy of ERUS is higher in diagnosing rectal cancer in stages T1, T2 and even in stage T3 with malignant tumor which is not occlusive. ERUS is less accurate for T staging of locally advanced and stenotic tumours.