Propensity score regression analysis of esophageal cancer treatment with surgery alone or neoadjuvant chemotherapy.

Abstract

405 Background: The aim of this study was to examine the outcomes of oesophageal adenocarcinoma (OC) treatment with either surgery alone (S), or with neoadjuvant chemotherapy (NAC) followed by surgery (NACS), by means of propensity score (PS) regression analysis, in order to examine whether the benefits reported in the MRC OE02 trial were reproducible in UK cancer network clinical practice. Methods: Consecutive patients undergoing potentially curative treatment for OC in a regional cancer network were studied. Multiple regression models, including PS were developed to account for confounding factors and the primary outcome measure was disease-free (DFS) and overall survival (OS). Results: A cohort of 440 patients was included in a regression analysis controlling for confounders (176 S, 264 NACS). NACS was associated with positive margin status (NACS vs. S, 42.4% vs. 26.7%, p<0.05), poor 5-year DFS (32.1% vs. 56.9, p<0.001), and poor 5-year OS (27.5% vs. 47.3%, p<0.001). On regression adjustment based on propensity scores, NACS was not associated with DFS (p=0.220) or OS (p=0.431). Mandard tumour regression grade (TRG) was significantly associated with DFS (hazard ratio (HR) 0.21,95% CI 0.07-0.70) and OS (HR 0.27 (95% CI 0.13-0.59). Five-year DFS and OS related to TRG was 63.6 and 61.5% vs. 8.0 and 8.6% (p<0.001) for good and poor responders respectively. Conclusions: Prescribing NAC to all OC patients risks delay in effective treatment of patients who are relatively chemo-resistant, given the variabilityin pathological response. Identifying OC patients who derive the most NAC benefit should be the focus.