OGC P39 Absolute lymph node yield <15 is associated with reduced overall survival in patients undergoing oesophagectomy for oesophageal cancer and is an important quality metric

Abstract

Abstract Background Surgical resection following neoadjuvant therapy with either chemotherapy or chemoradiotherapy remains the cornerstone of curative management of oesophageal cancer. In spite of this, there remains uncertainty regarding the optimal radicality of lymphadenectomy, and whether increasing lymph node yields confer a true survival benefit. This study aims to assess the impact of lymph node yield and lymph node ratio on survival following surgery for oesophageal cancer, in addition to identifying factors that may influence lymph node yield and radicality of resection. Methods Patients in a single centre undergoing oesophagectomy with curative intent from January 1, 2010 to December 31, 2020 were reviewed. Clinical and pathological variables were assessed, with univariable, multivariable, regression and survival analyses performed as appropriate. Regression with cut-point analysis was used to determine the optimal cut-off for lymph node ratio and for minimum number of nodes resected. Results Three hundred and ninety-seven patients underwent oesophagectomy in the study period, with 288 of these having a minimally invasive operation (MIE). Stage (stage 3 HR: 1.64 (1.02–2.62), p=0.04, stage 4 HR: 2.50 (1.43–5.01), p=0.001), positive margin status (HR: 2.62 (1.57–4.36), p<0.001), lymph node yield <15 (HR: 2.62 (1.57–4.36), p<0.001) and an elevated lymph node ratio (HR: 8.42 (2.85–24.90, p<0.001) predicted survival. Patients undergoing MIE had higher lymph node yields compared with open procedures (30.7 vs 25.3, p<0.001). Patients undergoing neoadjuvant chemoradiation had lower lymph node yields compared with those with no neoadjuvant therapy and those with neoadjuvant chemotherapy (26.4 vs 30.6 vs 36.8 respectively, p<0.001). Cut-point regression analysis determined lymph node ratio of <0.05 was associated with a survival benefit. Cut-point analysis also demonstrated that resecting more than 15 lymph nodes had an associated benefit, and 15 nodes is the minimum that should be resected, consistent with guidelines. Conclusions Lymphadenectomy is a cornerstone of resection of oesophageal cancer. Low lymph node yield and high lymph node ratio are associated with reduced overall survival. A lymph node ratio of <0.05 is associated with significant survival benefit. The minimum number of lymph nodes that should be resected in esophageal cancer is 15, consistent with current guidelines.