Abstract
BACKGROUND: The combined effect of tumor deposition (TD) and positive lymph node ratio (LNR) in colorectal cancer (CRC) is unknown. The aim of this study was to investigate the effects of TD and LNR in the prognosis of postoperative CRC patients. METHODS: We retrospectively reviewed 42,701 stage III CRC patients, including 42,470 patients from the Surveillance, Epidemiology, and End Results (SEER) database as a training set, and 231 patients from our hospital as a validation set. We analyzed the relationship of TD and LNR with overall survival (OS) by the Kaplan-Meier method and Cox regression analyses. RESULTS: Both TD-positive and high LNR (value ≥0.31) were related to worse OS in the training [hazard ratio (HR), 1.518; 95% confidence interval (CI): 1.471-1.565; HR, 1.902; 95% CI: 1.845-1.960, respectively] and validation sets (HR, 1.920, 95% CI: 1.989-3.310; HR, 1.989, 95% CI: 1.196-3.310, respectively). Patients with high TDs [>3] had significantly worse OS than those with low TDs [1-3] in both the training (P<0.001 by the log-rank test) and validation sets (P=0.007 by the log-rank test). Compared to CRC patients with negative TD combined with a low LNR, those with TD-positive combined with a high LNR had a 2.54-fold risk of death in the training set (HR, 2.538; 95% CI: 2.418-2.663) and a 3.90-fold risk in the validation set (HR, 3.897; 95% CI: 1.997-7.607). When combined with a high LNR, no differences were observed between patients with low TDs and high TDs in the two sets (P=0.12, log-rank test; P=0.72, log-rank test). CONCLUSIONS: The combined variable of LNR and TDs, regardless of the count of TDs, can accurately predict the risk of death in patients with CRC.