Impact of Lymph Node Retrieval on Prognosis in Elderly and Non-Elderly Patients with T3-4 Stage Rectal Cancer Following Neoadjuvant Therapy

Abstract

Purpose Obtaining the number of lymph nodes for radical surgery after neoadjuvant therapy for rectal cancer is controversial, this study aimed to compare prognostic factors in elderly versus non-elderly patients and identify the best lymph node interception value for prognosis. Methods A total of 7,894 patients with T3-T4 stage rectal cancer undergoing neoadjuvant chemotherapy were included in the study, comprising 2,787 elderly patients and 5,107 non-elderly patients from 2010 to 2019 were included in the the Surveillance, Epidemiology, and End Results (SEER) database. and an external validation cohort of 152 patients from the Longyan First Affiliated Hospital were analyzed. The study assessed overall survival (OS) and cancer-specific survival (CSS) using Cox regression analyses and identify the optimal lymph node count for surgical retrieval. Results Significant OS and CSS disparities were noted between elderly and non-elderly rectal cancer patients (P < 0.001), even after confounder adjustment (P < 0.001). The analysis found that 14 lymph nodes was the optimal number of lymph nodes to be cleared after neoadjuvant chemotherapy in patients with stage T3-T4 and showed that 14 lymph nodes was a better discriminator. External data validation at our centre confirmed these findings. Conclusion In this study 14 lymph nodes were considered the optimal threshold for patients with stage T3-T4 rectal cancer undergoing radical surgery after neoadjuvant therapy. Although the difference in CSS between taking 12 and 14 lymph nodes is not significant, this threshold helps to better differentiate prognosis.