Utility of EUS following endoscopic polypectomy of high-risk rectosigmoid lesions

BACKGROUND: The utility of endoscopic ultrasound (EUS) compared with standard white light endoscopy (WLE) following recent polypectomy of high-risk colorectal polyps is unknown. OBJECTIVE: To assess the incremental yield of EUS after endoscopic polypectomy of a high-risk rectal lesion. DESIGN: Retrospective cohort. SETTING: Tertiary referral center. MATERIALS AND METHODS: Patients referred for EUS following attempted endoscopic resection of a high-risk rectal neoplasm, defined as a tubulovillous adenoma, tubular adenoma with high-grade dysplasia, carcinoid, carcinoma in-situ or adenocarcinoma (CA). INTERVENTIONS: Sigmoidoscopy ± mucosal biopsy and EUS ± fine-needle aspiration (FNA) to evaluate for: (1) Residual polyp/tumor in the rectal wall or (2) peritumoral adenopathy. MAIN OUTCOME: Sensitivity and specificity for detection of residual neoplasia for WLE ± biopsy (WLE/BX) and EUS ± FNA for cancer (CA group) or benign disease (non-CA group). The incremental yield of EUS defined as: (1) Residual intramural neoplasia not present on WLE ± BX and; (2) abnormal peritumoral adenopathy. RESULTS: A total of 70 patients (mean age 64 ± 11 years, 61% male) with a final diagnosis of CA (n = 38) and non-CA (n = 32) were identified. There was no difference between the sensitivity and specificity of WLE alone (65% and 84%), WLE with biopsy (71% and 95%), and EUS (59% and 84%), for the detection of residual neoplasia (P > 0.05 for all). EUS identified 3 masses missed by WLE, all in the CA group. A malignant (n = 2) or benign (n = 3) node was identified in 5 (13%) CA patients; EUS-FNA in two showed residual malignancy in one and a reactive lymph node (LN) in one. No LNs were identified in the non-CA patients. LIMITATIONS: Retrospective design, incomplete follow-up in some patients. CONCLUSION: Following endoscopic polypectomy of high-risk rectal neoplasia, the incremental yield of EUS compared with WLE/BX for evaluation of residual disease appears limited, especially in patients with benign disease.