The Role of Para-Aortic Lymphadenectomy in Surgical Management of Patients with Stage N+ Rectal Cancer Below the Peritoneal Reflection

The goal of this retrospective study was to determine the effect of para-aortic lymphadenectomy on clinical outcome in patients with stage N+ rectal adenocarcinoma below the peritoneal reflection. A retrospective analysis was performed on the clinical outcome of 181 patients with stage N+ rectal adenocarcinoma below the peritoneal reflection who underwent total mesorectal excision (TME) with total pelvic lymph node (PLN) adenectomy, with or without para-aortic lymph node (PAN) adenectomy. Independent prognostic factors were determined by multivariate Cox regression analysis. Disease-free survival (DFS) was analyzed using Kaplan–Meier curves and the log-rank test. The incidence of PLN metastases was 39.2% (71/181) in all the patients, and the incidence of PAN metastases was 12% (12/100) in patients who received PLN + PAN adenectomies. The patients were divided into two groups: PLN adenectomy (n = 81) and PLN + PAN adenectomy (n = 100). There were no statistically significant differences in clinicopathological factors between the PLN adenectomy and PLN + PAN adenectomy groups. On univariate analysis, the gross tumor type (P = 0.012), histological differentiation (P = 0.013), CEA level (P = 0.019), T stage (P = 0.019), N stage (P < 0.0001), and the number of positive PLN sites (P < 0.0001) were associated with poor DFS. Gross tumor type (P = 0.031), N stage (P = 0.001), and the number of positive PLN sites (P < 0.0001) were independent prognostic factors for DFS as identified by multivariate Cox regression analysis. PLN + PAN adenectomy significantly improved DFS compared to PLN adenectomy alone in patients with noninfiltrating type (P = 0.001), but not in patients with infiltrating type (P = 0.075). PLN + PAN adenectomy significantly improved DFS compared to PLN adenectomy alone in patients with 0 or 1 positive PLN site (P = 0.001, P = 0.009 respectively), but not in patients with ≥2 positive PLN sites (P = 0.095). In the N1 and N2 stage groups, PLN + PAN adenectomy significantly improved DFS compared with PLN adenectomy alone (P = 0.001; P < 0.0001, respectively). Furthermore, mean DFS was longer in the absence of PAN metastasis (P < 0.0001). PAN metastases appear to be associated with reduced DFS. Total PAN adenectomy may improve DFS in patients with noninfiltrating type, stage III rectal cancer below the peritoneal reflection, who have <2 positive PLN sites.