Diagnostic value of endoscopic ultrasonography in staging of rectal cancer

Abstract

Objective To evaluate the diagnostic value of endoscopic ultrasonography (EUS) in staging of rectal cancer (RC). Methods From January 2015 to January 2017, the clinical data of 204 patients with RC and received EUS and surgery were retrospectively analyzed. Patients were divided into surgery alone group (155 cases) and preoperative neoadjuvant chemoradiation therapy (CRT) plus surgery group (49 cases). The preoperative staging by EUS and postoperative pathological staging of two groups were compared. Kappa test was performed for statistical analysis. Results Compared with postoperative pathologic diagnosis, the accuracy rate of EUS in the evaluation of invasion depth of RC in surgery alone group was 81.9% (127/155), and the accuracy rates in the diagnosis of Tis, T1, T2, T3 and T4 were 3/4, 11/13, 82.1%(32/39), 91.1%(41/45) and 74.1%(40/54), respectively, with a good consistency (kappa=0.751, P<0.01). However, the accuracy rate of EUS in the invasion depth of RC in CRT plus surgery group was 34.7% (17/49), and the accuracy rates in the diagnosis of T2, T3 and T4 were 1/13, 2/7 and 14/16, respectively, with a poor consistency (kappa=0.107, P=0.850). Compared with postoperative pathologic diagnosis, the diagnostic accuracy rate of EUS in evaluating regional lymph node metastasis in surgery alone group was 70.3% (109/155), and the accuracies in the diagnosis of cases with or without regional lymph node metastasis were 40.7% (24/59) and 88.5% (85/96), respectively, with a poor consistency (kappa=0.317, P<0.01). The diagnostic accuracy rate of EUS in evaluating regional lymph node metastasis of preoperative CRT plus surgery group was 51.0% (25/49), and the accuracies in the diagnosis of cases with or without regional lymph node metastasis were 5/11 and 52.6% (20/38), respectively, with a poor consistency (kappa=0.014, P=0.911). Conclusions EUS can accurately evaluate the depth of tumor invasion and lymph node metastasis in preoperative staging of RC, which may be helpful for determining clinical treatment strategy. However, for patients received CRT treatment, EUS has a limited value in diagnosing and staging the tumor. Key words: Rectal neoplasms; Endosonography; Neoplasm staging; Diagnosis