Clinical Significance of the Endoscopic Finding in Predicting Complete Tumor Response to Preoperative Chemoradiation Therapy in Rectal Cancer

Abstract

BACKGROUND: There are reports that suggest conservative treatment when a tumor shows clinically complete response (CR) after preoperative chemoradiotherapy in rectal cancer. The aim of this study is to investigate the association between endoscopic complete response (E-CR) and pathologic CR (pCR) and to determine the sensitivity and specificity of E-CR and its clinical utility after preoperative chemoradiotherapy in rectal cancer. METHODS: We analyzed prospectively collected data of patients with middle and lower rectal cancers who underwent preoperative chemoradiotherapy, between January 2010 and January 2015. RESULTS: Nineteen patients (17.9 %) showed E-CR, and 87 patients showed E-non CR. Twenty-three patients (21.7 %) were confirmed to have pCR. E-CR was closely associated with pCR (p < 0.001). E-CR reflected pCR with an accuracy of 88.7 %, sensitivity of 65.2 %, specificity of 95.2 %, PPV of 78.9 %, NPV of 90.8 %, and a p value of <0.001. CONCLUSIONS: E-CR after preoperative chemoradiotherapy in rectal cancer is significantly associated with pCR. However, a wait and see policy should be performed carefully with current endoscopic prediction for pCR to avoid inadequate treatment in patients who show E-CR after preoperative chemoradiotherapy.