Lymph node ratio and overall survival in patients with colon cancer: a prospective multicentre cohort study

Colorectal cancer (CRC) is a major health concern globally, with lymph node metastasis being a key factor in its spread. The lymph node ratio (LNR), defined as the ratio of pathologically positive lymph nodes to the total number of examined nodes, has been proposed as a prognostic marker in CRC. However, data from prospective cohort studies remain limited. This study aimed to evaluate the association between LNR and overall survival (OS) in patients with colon cancer in a prospective multicentre cohort. A prospective cohort study was conducted across seven Polish surgical centers enrolling 445 patients with primary colon cancer. The study collected survival data until September 30, 2022, focusing on patients aged 18-75 years eligible for radical surgery. Preoperative assessments included demographic information, Body Mass Index (BMI) and histopathological evaluation according to AJCC 8th edition. Surgical complications were graded using the Clavien-Dindo scale. The association between OS and LNR was analysed using a multivariable Cox proportional hazards model adjusting for selected clinical and surgical covariates. In the multivariable Cox model, LNR, BMI, and grade III or higher postoperative complications were independently associated with overall survival. For LNR, a 0.1-unit increase was associated with a 26% increase in the hazard of death (hazard ratio 1.26, 95% CI 1.07-1.48; p = 0.006). In this prospective multicentre cohort, lymph node ratio was associated with overall survival in patients with colon cancer, alongside body mass index and the severity of postoperative complications. These findings suggest that LNR may represent a clinically relevant prognostic marker and warrant further investigation in studies specifically designed to compare its prognostic performance with established nodal staging systems.