646 PREDICTING RESPONSE TO NEOADJUVANT CHEMOTHERAPY IN PATIENTS WITH OESOPHAGEAL ADENOCARCINOMA

Abstract

Abstract Neoadjuvant chemotherapy is often used prior to surgical resection for oesophageal adenocarcinoma but remains ineffective in a high proportion of patients. The histological Mandard tumour regression grade is used to determine chemoresponse but is not available at the time of treatment decision-making. The aim of this study was to identify factors that predict chemotherapy response prior to surgery. Methods A prospectively collected database of patients undergoing surgical resection for oesophageal adenocarcinoma from a high-volume UK institution was used. Patients were subcategorised using pathological tumour response into ‘responders’ (Mandard grade 1–3) and ‘non-responders’ (Mandard grade 4&5). Multivariable logistic regression analysis was performed to calculate crude and adjusted odds ratios (OR) with 95% confidence intervals (CI) for responder status adjusting for a variety of parameters. Receiver-operator curves (ROC) were calculated. Results Among 315 patients included, 102 (32%) were responders and 213 (68%) non-responders. A decrease in radiological tumour volume (OR 1.92 95%CI 1.02–3.62; p = 0.05), a ‘partial response’ RECIST score (OR 7.16 95%CI 1.49–34.36; p = 0.01), a clinically improved dysphagia score (OR 2.79 95%CI 1.05–7.04; p = 0.04) and lymphovascular invasion (OR 0.06 95%CI 0.02–0.13; p = 0.000) influenced responder status. ROC curve analysis for responder status utilising all available parameters had an area under the curve (AUC) of 0.86. Conclusion This study has highlighted the potential for using pre-defined factors to identify those patients who have responded to neoadjuvant chemotherapy, prior to surgical resection, potentially facilitating a more individualised therapeutic approach.