Prognostic Significance of Lymph Node Density in Pathological Node Positive Urothelial Carcinoma of the Bladder -Upfront Surgery and Post Neoadjuvant Chemotherapy Cohorts

Aim: To validate the role of lymph node density as a prognostic marker in patients undergoing primary surgery and postneoadjuvant therapy in pathological node-positive urothelial bladder carcinoma. Materials and Methods: Retrospective analysis of 503 patients who underwent radical cystectomy from 2006 to 2019 for muscle-invasive urothelial bladder carcinoma, of which 152 patients with pathological node-positive disease were analyzed. Demographic details, pathological findings, treatment details, disease-free, and overall survival were documented. X tile program analysis was used to divide patients with positive lymph nodes into 3 groups: LD1: <= 7, LD2 :>7 to <15, LD3: >15, and the optimal cut-off value obtained was 15%. To evaluate the impact of lymph node ratio, patients with positive lymph nodes into 3 categories for each cut-off point estimation method, the application generates the histogram, Kaplan-Meier plot and calculates hazard ratio, confidence intervals and P-values. Univariate and multivariate cox regression analysis was done with a P-value of <.05, considered significant. Results: One hundred fifty-two patients (30.2%) had pathological nodal metastasis, with 87 of them having perinodal extension. Ninety-six underwent primary surgery, and 56 were postneoadjuvant chemotherapy. The median follow-up was 55.42 months. 68 of the 152 node-positive patients died of the disease. Median number of lymph nodes removed was 17.11. Lymph node density divided into tertiles were LD1 <7%, LD2 7-<15%, LD3 >15% showed 5-year RFS 40.5%,29.3%, 22.6% and 5 year OS was 55.5%, 42.4%,32.1% respectively. Cox regression analysis showed that age less than 55 years ,higher tumor stage, lymphovascular invasion, and higher lymph node ratio were significant in univariate and multivariate analysis. The lymph node density cut-off value of 15% was substantial among node-positive patients (P = .027), and subgroup analysis in upfront surgery with the adjuvant treatment group and postneoadjuvant chemotherapy group was also significant (P =.021). Conclusion: Pathological higher T stage, Age <55 years, Lymphovascular invasion, adjuvant chemotherapy , adjuvant radiation treatment and lymph node density had prognostic significance in both cohorts of patients who underwent upfront surgery and neoadjuvant chemotherapy. Lymph node density cut-off value of <15% was prognostically significant.