Impact of positive-to-total lymph node ratio on prognosis in stage 3 colorectal cancer. A multicenter study

BACKGROUND: Colorectal cancer remains a health problem despite advances in diagnostic and treatment methods. This study aimed to determine the impact of positive-to-total lymph node ratio on survival in colorectal cancer. METHODS: Patients with stage 3 colorectal cancer were included. Patients age; sex; operation type (emergency or elective); tumor size, grade, and location; TNM stage; vascular and perineural invasions; numbers of lymph nodes examined and negative lymph nodes, positive-to-total lymph node ratio, and administration of postoperative chemotherapy were examined. RESULTS: Median follow-up period was 34.7 months. Most patients were in stage 3b (67.9%), and the median number of dissected lymph nodes was 15. The number of metastatic lymph nodes, positive lymph node ratio, and negative -to-positive lymph node ratio were 3, 16.7, 11, and 5, respectively. The overall survival rate was 48.6%. Mean life expectancy was 51.5 months. Multivariate Cox regression analysis revealed positive-to-total lymph node ratio >23.3%, age, and absence of postoperative chemotherapy as risk factors for overall survival (p<0.05). Positive-to-total lymph node ratio >23.3% was associated with poor overall survival and 3.726-fold poorer survival. DISCUSSION: Positive-to total lymph node ratio >23.3% is a risk factor affecting overall survival in stage 3 colorectal cancer. Increased positive-to-total lymph node ratio (>23.3%) is associated with poor overall survival.