Impact of Metastatic Lymph Node Ratio on Survival and Prognosis in Rectal Carcinoma: A Retrospective Cohort Study

Objective This study aimed to evaluate the impact of the metastatic lymph node ratio (mtLNR) on survival outcomes and prognosis in patients with rectal carcinoma, in comparison with other clinicopathological factors. Methods A retrospective cohort analysis was conducted on 97 patients with rectal adenocarcinoma who underwent surgical treatment at Erol Olçok Training and Research Hospital between January 2017 and December 2022. The inclusion criteria consisted of patients over 18 years of age and the absence of hematological disorders or concurrent inflammatory conditions. The patients' demographic data, tumor characteristics, surgical details, lymph node (LN) status, mtLNR, and survival outcomes were analyzed. The optimal cutoff value of mtLNR for predicting mortality was determined using receiver operating characteristic (ROC) curve analysis. Kaplan-Meier survival analysis was employed to estimate overall survival (OS) and disease-free survival (DFS), and differences between groups were evaluated using the log-rank test. The Cox proportional hazards model was used to calculate hazard ratios (HRs) for all-cause mortality. Statistical significance was set at p<0.05. Results The mean age of the patients was 70.31 ± 11.57 years, with 65.98% being male. Low anterior resection (LAR) was performed in 83.51% of the patients, and laparoscopic surgery was conducted in 26.8%. The median OS for the entire cohort was 24 months (range: 3-60). Patients were divided into two groups based on mtLNR, with the cutoff value set at 0.2183. A high mtLNR was significantly associated with poorer DFS and OS (p=0.021 and p=0.003, respectively). Moreover, patients with an mtLNR>0.2183 exhibited significantly higher rates of recurrence, lymphovascular invasion (LVI), and perineural invasion (PNI) compared to those with a lower mtLNR (all p<0.001). The optimal cutoff value of mtLNR predicted mortality with a specificity of 81.4% and a sensitivity of 48.1% (area under the curve (AUC) 0.662, p=0.012). Kaplan-Meier analysis showed a significant difference in survival between the two groups; the risk of all-cause mortality was 3.71 times higher in patients with mtLNR>0.2183 (p=0.002). Conclusion The mtLNR is a strong determinant of survival and prognosis in patients with rectal carcinoma. High mtLNR values are associated with worse survival outcomes and more aggressive tumor characteristics. The findings suggest that mtLNR should be considered in clinical decision-making processes. These results indicate that mtLNR could be a valuable prognostic tool in clinical decision-making.