Prognostic impact of the Lymph node ratio in rectal cancer patients who underwent preoperative chemoradiation

Abstract

The purpose of this study was to investigate the prognostic impact of the lymph node ratio (LNR) in ypN-positive rectal cancer patients who received preoperative chemoradiation (preop-CRT). A total of 75 patients diagnosed as node-positive after undergoing preop-CRT followed by curative resection were enrolled. Patients were categorized into two groups based on their median LNR, 0.143. The median metastatic and retrieved lymph node numbers were 2.0 (range: 1-79) and 18.0 (range: 5-80). Abdominoperineal resection, circumferential resection margin involvement and higher LNR were proven to be independent adverse prognostic factors affecting survival in the multivariate analysis including LNR as a covariate. Of the 47 patients with ypN1, 35 (74.5%) showed a lower LNR (N1G1) and 12 (25.5%) showed a higher LNR (N1G2). The N1G1 group showed better overall survival than the N1G2 group (P = 0.018). There was no difference between the survival rates of the N1G2 group and the ypN2 group (P = 0.987). LNR is an independent prognostic factor after preop-CRT for rectal cancer. LNR showed better prognosis stratification than the ypN stage. Therefore, LNR should be considered as an additional prognostic factor in node-positive rectal cancer after preop-CRT.