P213 prognostic significance of changes in lymph node morphology on survival in esophageal cancer after neoadjuvant therapy: a systematic review and meta-analyses

Abstract Aim To assess the prognostic significance of lymph node regression or downstaging following neoadjuvant therapy for esophageal cancer. Background and methods The prognostic value of histomorphologic regression in the primary esophageal cancer has been established, whilst the impact of lymph node response on survival still remains unclear. An electronic search was performed to identify articles evaluating lymph node regression or downstaging after neoadjuvant chemo- or chemoradiotherapy. Random effects meta-analyses were performed for regression and downstaging and primary outcome was the hazard ratio (HR) for overall mortality. Survival data were compared between patients with complete regression and those with partial or no response. Histopathological tumor regression in lymph nodes was defined by the absence of viable cells or degree of fibrosis. Furthermore, survival of patients with downstaged lymph nodes to N0 were compared to those with positive nodes following treatment. Results Eight articles were included, 4 of which assessed tumor regression (number of patients=789) and 4 assessing downstaging (number of patients=1937). Complete tumor regression (average rate of 30.0%) in the lymph nodes was associated with higher survival [HR= 0.63, 95% CI (confidence interval) = 0.43 – 0.92; p=0.017] (figure 1). Lymph nodes downstaging (average rate of 47.6%) had improved survival compared to node positivity (HR = 0.38, 95% CI = 0.29 – 0.50; p<0.0001) (figure 2). Conclusion A prognostic benefit was seen in patients with good lymph node response to neoadjuvant therapy, suggesting this should be used as an important additional prognostic marker in staging and in comparative evaluation of different neoadjuvant regimes.