Association of the Number of Negative Lymph Nodes Removed with Overall Survival and Recurrence Rates in Patients with Colorectal Cancer Following Surgery: A Multicenter Retrospective Cohort Study.

PURPOSE: This study aimed to evaluate the effect of the number of negative lymph nodes (NLNs) removed during surgery on overall survival (OS) and recurrence-free survival in patients with colorectal cancer following surgery. METHODS: This multicenter retrospective cohort study reviewed the medical profile of 1408 CRC patients who underwent surgery at one of our academic medical centers between 2012 and 2022. Based on the number of NLNs removed, patients were classified into three groups: 322 patients (< 7 NLNs), 668 (8–14 NLNs), and 418 patients (> 14 NLNs). The effect of the number of NLNs removed on OS and RFS rates was evaluated. Demographic characteristics, tumor characteristics, and pathological findings of the patients were obtained by reviewing their medical records. RESULTS: The OS rate in patients with < 7, 8–14, and > 14 NLNs removed were 54.2%, 67.1%, and 79.2%, respectively (Log-rank = 64.2, P 0.001). The RFS rates in patients with < 7, 8–14, and > 14 NLNs removed were 49.3%, 60.4%, and 74.4%, respectively (Log-rank = 68.9, P 0.001). Cox multivariate analysis showed that the number of NLNs removed > 14 was significantly associated with improved OS (HR: 0.69, 95% CI: 0.51, 0.87; P: 0.001) and RFS (HR: 0.66, 95% CI: 0.50, 0.83; P: 0.001) rates in CRC patients. In addition, age ≥ 55 years, comorbidities, higher tumor stage (> II), depth of invasion (> T2), higher BMI, tumor location (rectum vs. colon), non-adjuvant therapy and poor tumor histology were significantly associated with reduced OS and RFS in CRC patients. CONCLUSION: Removing more NLNs during surgery can improve OS and RFS in patients with CRC. Paying attention to the number of NLNs removed during surgery can be a key factor in improving the prognosis of OS and RFS in CRC patients after surgery.