P1.005. Preliminary Pilot Study Cohort Results - Cost-Effective Surveillance Strategies and Prediction of Cancer Recurrence After Endoscopic Therapy for Barrett’s Esophagus (Endeavor)

Abstract

Abstract Topic Esophageal Cancer: Barrett‘s Esophagus: High-Grade Dysplasia and Early Invasive Cancer Background In many European countries, esophageal adenocarcinoma (EAC) incidence is increasing [1]. Barrett’s esophagus(BE), strongly associated with EAC, can progress via dysplasia to early and invasive adenocarcinoma [2]. Endoscopic treatment is the mainstay for early mucosal cancer (T1a/b) but requires intense post-treatment surveillance [3]. This results in overtreatment in most, and undertreatment in only a subset of patients [4]. The ENDEAVOR consortium, with over 10 partners from 8 European countries, will execute a 5-year project to develop a risk stratification model guiding treatment and surveillance. Below, preliminary results from the pilot study. Methods A total of 60 patients with BE and a visible lesion on endoscopy will be included in this study. Patients will be evaluated for endoscopic resection, with ablation therapy as needed. Forceps biopsies, brush biopsies and blood samples are taken before and after endoscopic resection. From these samples, clonal diversity measurements for HER-2, cMYC and CEP-17 are determined. Using these results, a determination of low or high clonal diversity is made. The degree of clonal diversity will be correlated to histopathological risk factors (lymphovascular invasion, differentiation grade, invasion depth) and recurrence events. Results Ongoing recruitment is at 33 patients. The population includes 6,1% female gender, mean age 67,27 (SD 10,42) and mean BMI 27,93 (SD 5,91). Median BE segment length is C1M3, 39,3% short-segment Barrett (<3cm maximum extent), and hernia diaphragmatica was present in 46,4% of patients. Paris classification lesion types consisted of Is (7; 20,59%), IIa (15; 44,12%), IIb (6; 17,65%), IIc (4; 11,76%). There were no Ip or III lesions included so far, 2 lesions (5,88%) were not classifiable. Of the 26 endoscopic resections performed so far, en bloc resection was performed in 23/26 procedures (88,46%). Histopathology staging has been obtained for 18 specimens, of which 9 were T0 (60%), 8 were T1a (33,33%) and 1 was T1b (6,67%) (see Table 1). In the 14 patients that have undergone endoscopy after endoscopic resection, There have been no recurrences registered so far, with average follow-up time after endoscopic resection of 3,54 months. Conclusion Our population includes an important number of patients with short-segment BE. With ongoing discussion about the surveillance intervals for short-segment BE, future data on recurrence rates in this subgroup will prove valuable. Continued follow-up to detect recurrences and biomarker analysis is being conducted.