LODDS is Superior to Lymph Node Ratio for the Prognosis of Node-positive Rectal Cancer Patients Treated with Preoperative Radiotherapy

Purpose Yielding pathologic-lymph node ratio (yp-LNR) was considered to be a better staging system than yp-N stage in rectal cancer patients treated with preoperative radiotherapy (pre-RT). We aimed to compare the predictive ability of yielding pathologic log odds of positive lymph nodes (yp-LODDS) with that of yp-LNR for cancer-specific survival (CSS) in stage III rectal cancer patients treated with pre-RT. Methods We analyzed stage III rectal cancer patients treated with pre-RT in the Surveillance, Epidemiology and End Results (SEER) database. Patients were classified into 4 groups, yp-LNR1 to 4, based on the LNR cutoff points 0.25, 0.50, and 0.75. Subjects were categorized into 5 groups, yp-LODDS1 to yp-LODDS5, based on the LODDS cutoff points −1, 0, 1, and 2. Univariate and multivariate Cox proportional hazards models were performed to analyze the risk factors for survival outcome. Results A total of 4,612 patients were included from the SEER database. Patients in the yp-LNR4 group could be further divided into yp-LODDS4 and yp-LODDS5 groups with 5-year CSS of 47.6% and 31.5%, respectively (p