P107 PREDICTION OF A POSITIVE CIRCUMFERENTIAL RESECTION MARGIN IN ADENOCARCINOMA OF THE ESOPHAGUS

Aim To determine if a positive circumferential resection margin (CRM) can be predicted in patients with esophageal adenocarcinoma undergoing neo-adjuvant chemotherapy prior to surgery Methods 223 patients were included in this study. Multivariable analyses of clinico-pathological and computed tomography (CT) imaging predictors were performed to evaluate the likelihood of a positive CRM at initial staging and following neoadjuvant chemotherapy, with prediction models constructed. Area under curve (AUC) with 95% confidence interval (CI) from 1000 bootstrapping was assessed. Results Advanced clinical T-stage (T3-4) (odds ratio, OR 2.93 95%CI 1.03-9.48) and poor tumor differentiation (OR 2.84, 95%CI 1.39-6.01) were independently associated with an increased risk of a positive CRM. Non response to chemotherapy as estimated by CT independently corresponded with an increased risk of CRM positivity (OR 3.38 95% CI 1.43-8.50). Additional CT evidence of local invasion/pleural thickening and higher CT tumor volume (14cm3) improved the performance of a prediction model, including all above parameters; with AUC (c-index) of 0.76 (0.68-0.83). Conclusion Combining advanced clinical T-stage, poor tumor differentiation, CT non-response to chemotherapy, higher CT tumor volume and local invasion may be helpful in selecting patients for intensification of neo-adjuvant treatment prior to resection.