Endorectal ultrasonography performance in staging rectal cancer before and after neoadjuvant chemoradiotherapy.

Aim: To evaluate accuracy of endorectal ultrasonography (ERUS) both in staging and restaging rectal cancer after neoadjuvant chemoradiotherapy treatment.
Methods: In a group of 80 patients with rectal cancer, we retrospectively selected 67 patients and divided in two groups: 41 patients affected by a stage I were investigated with a single preoperative endorectal sonography; 26 patients with locally advanced rectal cancer (stage II or more) were restaged after neoadjuvant treatment, which consisted of 5,040 cGy in 28 daily fractions associated with continuous infusion of 5-Fluorouracil. All patients underwent surgery and ERUS findings were subsequently compared with histological findings.
Results: Diagnostic accuracy of ERUS in the first group of patients was high: in fact T-staging was accurate in 85% of cases. Results in the second group were significantly less accurate, with a correct T-staging just for 47% of cases. Nodes involvement was correctly evaluated in 86% of cases for the first group and in 63% of cases for the second one.
Conclusions: Endorectal sonography is a valid staging modality for early rectal malignancy. Advanced cancer is treated with neoadjuvant preoperative chemoradiotherapy which is associated with better outcome than postoperative treatment. We found endorectal sonography, based on the layer model of rectal wall, often fails restaging and we think we have to develop new criteria for a correct preoperative assessment after neoadjuvant chemoradiation.
Key Words: Endorectal ultrasonography, Neoadjuvant chemoradiotherapy, Rectal cancer, Staging.