Efficacy Of Endoscopic Ultrasonography In Preoperative Staging Of Rectal Cancer

BACKGROUND: Rectal cancer is one of the most common malignancies in digestive tract. In China, the incidence of rectal cancer shows an increasing trend and more than 30% of patients with rectal cancer are younger than 40 years old. Digital rectal examination and electronic colonoscope are the main methods to discover rectal cancer. Accurate preoperative staging is helpful for the choose of therapeutic regimen,and is also the key to improving the five-year survival rate.AIM: To evaluate the accuracy, sensitivity and specificity of endoscopic ultrasonography for preoperative T and N staging, and access the efficacy of endoscopic ultrasonography in preoperative staging of rectal cancer.METHODS: A total of 70 patients with biopsy proved primary rectal cancer between2013 and 2016 were invited to take part in this study. Then we compare tumor staging using endoscopic ultrasonography with postoperative pathological results in order to ensure the efficacy of EUS.RESULTS: This study included 70 patients, 39 males accounting for 55.71% and 31 females accounting for 44.29%. These patients’ average age was 58 years old. The number of patients diagnosed by endoscopic ultrasonography as T1, T2, T3, T4 was 8,13, 37, 12. But ensured by postoperative pathology, there were 10 patients diagnosed as T1 phase, 3 patients overstaging. There were 12 patients diagnosed as T2 phase, 1patient understaging and 4 patients overstaging. There were 36 patients diagnosed as T3 phase, 3 patients overstaging and 2 patients understaging. The last 12 patients were diagnosed as T4 phase, 4 patients understaging. The each accuracy for T1, T2,T3, T4 was 70.00%、58.33%、86.11%、66.67%. And the overall accuracy for T staging was 75.71%. 52 patients were diagnosed by endoscopic ultrasonography as lymph node negative and 18 patients diagnosed as lymph node positive. Contrasted by postoperative pathology, there were 3 patients with positive lymph node diagnosed by EUS in 40 patients with negative lymph node and 15 patients with negative lymph node diagnosed by EUS in 30 patients with positive lymph node. The overall accuracy,sensitivity and specificity were 74.29%, 50.00% and 92.50%.CONCLUSION: The endoscopic ultrasonography provides good predictive data for T staging of rectal cancer, especially for T3 phase, which is beneficial for the choose of clinical treatment strategies. The accuracy and specificity of endoscopic ultrasonography for lymph node staging was also high, but with poor sensitivity. So the combination of EUS with other imaging techniques such as CT and MRI will improve the detection rate of malignant lymph node.