Objective: To evaluate the accuracy of endorectal ultrasound (ERUS) in predicting the circumferential resection margin (CRM) and maximum tumor thickness (MTT) of in T3 rectal cancer.
Methods: Clinicl data of 53 patients with pT3 rectal cancer admitted to the Department of General Surgery in the Peking Union Medical College Hospital from June 2011 to January 2014 were retrospectively analyzed. CRM and MTT measured by ERUS were compared with corresponding pathologic measurements to assess the accuracy of ERUS diagnosis.
Results: ERUS correctly predicted CRM status in 52 patients (98.1%, 52/53), whose sensitivity was 100%, specificity was 97.8%, positive predictive value was 85.7%, and negative predictive value was 100%. ERUS correctly predicted MTT status in 51 patients (96.2%, 51/53), whose sensitivity was 100%, specificity was 95.5%, positive predictive value was 66.6%, and negative predictive value was 100%. In the Bland and Altman plot, the agreement between ERUS and pathology was good.
Conclusion: Endorectal ultrasonography can accurately diagnose CRM and MTT, which can satisfy the clinical need for preoperative staging of rectal cancer.