Transrectal ultrasonography in the staging of rectal cancers

Introduction: Transrectal ultrasonography (TRUS) is an essential method in the staging of rectal cancers. According to the ICCN guidelines TRUS has the same priority as endoscopy. On the basis of literature data, sensitivity of T and N staging by TRUS is higher than by other radiological examination.

Aims and methods: The aim of our study was to compare the accuracy of TRUS in the TN staging of rectal cancer with the postoperative histopatological findings and with other radiological methods and to examine the influence of preoperative neoadjuvant therapy on the staging and on the accuracy of TRUS.

Results: 71 patients with rectum carcinoma were examined in overall 83 cases with rectal ultrasound to assess the stage of the rectal tumor. Patients, being suitable for our study, were divided into three groups. [TRUS was performed both before and after (n=12); only after (n=9) neoadjuvant treatment and in patients (n=13) who did not receive neoadjuvant therapy]. Sensitivity was found to be 100% in T and 75% in N staging in cases without neoadjuvant treatment. Sensitivity of TRUS performed after neoadjuvant radiotherapy proved to be lower (T staging: 71%, N staging: 50%). However, the accuracy of TRUS (40% in both T and N stages) before neoadjuvant therapy is not so reliable compared with the postoperative histological staging. Although majority of these cases were overstaged, efficacy of the neoadjuvant treatment could not be determined by TRUS. The accuracy of CT and MRI examinations for T staging was 62%, and for N staging 52%.

Conclusion: TRUS has high sensitivity and it has proven useful for the assessment of T stage in rectal carcinoma, although its accuracy worsens after pre and postneoadjuvant treatment. Metastases should be detected by other radiological methods.