Prognostic value of tumor deposits and positive lymph node ratio in stage III colorectal cancer: a retrospective cohort study.

Abstract

In colorectal cancer (CRC), tumor deposits (TD) have been used to guide the N staging only in node-negative patients. It remains unknown about the prognostic value of TD in combination with positive lymph node ratio (LNR) in stage III CRC. We analyzed data from 31,139 eligible patients diagnosed with stage III CRC, including 30,230 from the Surveillance, Epidemiology, and End Results (SEER) database as a training set and 909 from two Chinese hospitals as a validation set. The associations of TD and LNR with cancer-specific survival (CSS) and overall survival (OS) were evaluated using the Kaplan-Meier method and Cox regression models. Both TD-positive and high LNR (value≥0.4) were associated with worse CSS in the training (multivariable hazard ratio [HR], 1.50; 95% confidence interval [CI], 1.43-1.58 and HR, 1.74; 95% CI, 1.62-1.86, respectively) and validation sets (HR,1.90; 95%CI, 1.41-2.54 and HR,2.01; 95%CI, 1.29-3.15, respectively). Compared to patients with TD-negative and low LNR (value<0.4), those with TD-positive and high LNR had a 4.09-fold risk of CRC-specific death in the training set (HR, 4.09; 95% CI, 3.54-4.72) and 4.60-fold risk in the validation set (HR, 4.60; 95% CI, 2.88-7.35). Patients with TD-positive/H-LNR CRC on the right side had the worst prognosis (P<0.001). The combined variable of TD and LNR contributed the most to CSS prediction in the training (24.26%) and validation (32.31%) sets. A nomogram including TD and LNR showed satisfactory discriminative ability, and calibration curves indicated favorable consistency in both the training and validation sets. TD and LNR represent independent prognostic predictors for stage III CRC. A combination of TD and LNR could be used to identify those at high risk of CRC deaths.