Outcomes of Endoscopic Resection for Colorectal Polyps With High-Grade Dysplasia or Intramucosal Cancer

Background and Aims: Little is known about the outcomes of endoscopic resection (ER) for patients with colorectal adenomas (CRAs) with high-grade dysplasia (HGD) or intramucosal cancer (IMCA). This study aimed to estimate the rate of local/malignant recurrence, identify the predictive factors for local recurrence (LR), and evaluate the treatment outcomes of recurrence after ER for HGD/IMCA. Methods: A retrospective review was performed to identify patients who underwent ER for HGD/IMCA in 2 academic medical centers. Risk factors for LR were determined by Cox regression analysis. Results: Overall, 188 lesions with HGD/IMCA were included; 61 lesions were removed by en-bloc ER (e-ER), whereas 127 lesions were removed in a piecemeal ER (p-ER). The mean lesion size was 20.3 mm. Of the 125 patients who underwent follow-up, local adenoma recurrence occurred in 31 (23%), and malignant recurrence occurred in 2 (1.6%) patients at a median follow-up of 16 months. HGD/IMCA ≥ 4 cm removed by p-ER have the greatest hazard ratio (HR = 21.5; 95% CI 2.5-180.5; P = 0.005) for LR, compared with the HGD/IMCA < 4 cm removed by e-ER. Surgery was performed in 3.2% of patients after a complete ER, all after p-ER. Of all patients who had LR, 22.6% (7/31 patients) had recurrent adenomas despite repeat ER attempts after a mean of 1.9 ± 0.79 procedures from the index ER. Conclusion: Our study demonstrates a high rate of LR (23%) after ER of CRAs with HGD/IMCA with a rate of malignant recurrence of 1.6%, especially after p-ER. Thus, e-ER should be preferred for these lesions whenever technically feasible.