Prognostic Implications of the Number of Retrieved Lymph Nodes of Patients with Rectal Cancer Treated with Preoperative Chemoradiotherapy

The impact of the number of retrieved lymph nodes (LNs) on oncological outcomes in patients with rectal cancer remains unclear. This study was designed to evaluate the prognostic implications of the number of retrieved LNs in patients with rectal cancer receiving preoperative chemoradiotherapy (CRT). The study cohort consisted of 859 patients with locally advanced (cT3-4 or cN+) mid to low rectal cancer that had been treated with preoperative CRT and radical resection between 2000 and 2009. Multivariate analysis and the Kaplan-Meier method were used to evaluate the influence of the number of retrieved LNs on disease-free survival (DFS). The median number of LNs retrieved from included patients was 13 (interquartile range [IQR] 9-17). Multivariate analysis confirmed the independent prognostic importance of the number of retrieved LNs on DFS (hazard ratio = 0.97, 95 % confidence interval = 0.95-0.99, p = 0.029). The 3-year DFS rate in patients with yp stage II rectal cancer was associated with the total number of retrieved LNs. DFS was associated with the number of LNs retrieved from patients with rectal cancer who received preoperative CRT, especially among patients with ypT3-4 N0 stage tumors. The oncological importance of the number of retrieved LNs should be considered when treating these patients.