Value of Endorectal Utrasound for Staging Rectal Cancer Following Neoadjuvant Chemoradiation Therapy

  Objective  To assess the value of endorectal ultrasound (ERUS) for staging rectal cancer after neoadjuvant chemoradiation.

  Methods  We retrospectively analyed the clinical data of 62 patients with rectal cancer between September 2011 and September 2012 in our hospital. ERUS was performed before and after chemoradiation therapy in all patients. All patients underwent subsequent total mesorectal excision (TEM) and completed pathologic staging. The results of ERUS were compared with the postoperatively pathologic staging.

  Results  After chemoradiation, 8 patients had no residual disease at pathologic staging(pT0N0)which was not correctly predicted by ERUS. Of 30 patients who responded well to the chemoradiation therapy, only 7 achieved correct ultrasonic staging (uT). The overall accuracy of ERUS for uT was only 40.3%(25/62), while 36 patients (58.1%)were overstaged and 1 patient (1.6%)was understaged. The sensitivity, specificity, and positive and negative predictive values for nodal staging were 60.0%, 84.6%, 42.9%, 91.7%, respectively.

  Conclusions  The ERUS uT of rectal cancer after chemoradiation is inaccurate, especially in patients with evidence of response. Meanwhile, ERUS cannot reliably predict tumor pathological complete remission. However, ERUS has high specificity and negative predictive value for nodal staging and therefore is valuable in predicting the prognosis.