Mo1638 ENDOSCOPIC RESECTION FOLLOWED BY SURGERY IN T1 COLORECTAL CANCER WITH HIGH RISK HISTOLOGICAL FEATURES DOES NOT AFFECT CANCER-RELATED LONG-TERM OUTCOMES

Abstract

We aimed to identify if endoscopic resection of T1 colorectal cancer (CRC) before surgical resection (secondary surgery) unfavorably affects cancer-related long-term outcomes compared to surgery without prior endoscopic resection (primary surgery). We included patients who underwent surgery for T1 CRC with at least one high-risk histological features (poor differentiation, deep submucosal invasion, lympho-vascular invasion, and/or positive/indeterminate resection margins) at our institution between 2011-2016. Medical records, histology reports and results of endoscopic and radiologic examinations were reviewed retrospectively. Radical abdominal surgery was performed in 852 patients (388 primary and 464 secondary surgeries). Surgical trans-anal excision was performed in 21 patients (9 primary and 12 secondary surgeries). During follow-up periods of 51.4±18.3 months, cancer recurrence occurred in 20 patients. Five-year survival rates did not differ between primary and secondary abdominal surgery groups (97.3% vs. 98.5%, p = 0.294). Analyses stratified by nodal stages and number of high-risk histological features did not show any difference in cumulative survival rates. However, patients with secondary abdominal surgery showed higher 5-year survival rates compared to secondary trans-anal surgery (98.6% vs. 90.9%, p < 0.001). In multivariable Cox regression analysis, preoperative serum CEA level was an independent risk factor for cancer recurrence. Prior endoscopic resection was not an independent risk factor for cancer recurrence. Endoscopic resection of T1 CRC with high-risk histological features did not affect cancer-related long-term outcomes. Therefore, endoscopic resection of suspected T1 CRC can be performed without fear for worsening the oncological prognosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)