Neoadjuvant therapy in relation to lymphadenectomy and resection margins during surgery for oesophageal cancer

Differences in lymph node yield and tumour-involved resection margins comparing neoadjuvant therapy plus surgery with surgery alone for oesophageal cancer are unclear. Patients who underwent oesophageal cancer surgery in Sweden in 1987-2010 were included. Patients treated with neoadjuvant therapy were compared with those who underwent surgery alone. Outcomes were the number of examined lymph nodes (main outcome), number metastatic lymph nodes, and resection margin status. Rate ratios (RRs) and 95% CIs of lymph node yield were calculated by Poisson regression, and odds ratios (ORs) and 95% CIs of resection margin status by multivariable logistic regression, both adjusted for confounders. Among 1818 patients, 587 (32%) had received neoadjuvant therapy and 1231 (68%) had not. Lymph node yield was lower in the neoadjuvant therapy group (median 6 versus 8; adjusted RR 0.75, 0.73-0.78). Fewer metastatic nodes were identified following neoadjuvant therapy (median 0 versus 1; adjusted RR 0.76, 0.69-0.84). Neoadjuvant therapy associated to decreased risk of tumour-involved resection margins when adjusted for confounders except T-stage (OR 0.52, 0.38-0.70), but the association did not remain after adjustment for T-stage (OR 0.91, 0.64-1.29). Neoadjuvant therapy seems to decrease the lymph node yield and decrease the risk of tumour-involved resection margins by shrinking primary tumour.