Mapping Patterns of Pelvic Lymph Node Metastasis in Bladder Urothelial Carcinoma: Implications for Personalized Pelvic Radiation Therapy.

Abstract

This study aimed to evaluate the association between primary bladder urothelial carcinoma T-stage, G-grade, and pelvic lymph node metastasis (PLNM), and to delineate the location of metastatic pelvic lymph nodes across different T-stage and G-grade combinations. Surgical and pathologic data from 1555 patients who underwent radical cystectomy with pelvic lymph node dissection for bladder urothelial carcinoma at our hospital between October 2014 and September 2024 were collected and analyzed. Pelvic lymph nodes were anatomically classified into 6 regions: peri-vesical, internal iliac/obturator, external iliac, presacral, common iliac, and paraortic. Descriptive statistics were used to quantify PLNM rates and distribution patterns by T-stage and G-grade. Multivariate logistic regression identified independent predictors of PLNM. Of the 1555 patients analyzed, 297 (19.1%) exhibited pathologically confirmed PLNM. Stratified by T-stage, PLNM rates progressively increased from 2.6% in Ta/Tis/T1 patients to 11.0% in T2, 29.8% in T3, and 50.0% in T4. Similarly, G-grade stratification revealed no lymph node involvement in G1 patients (0%), whereas PLNM rates rose to 2.9% in G2 and 23.9% in G3. Notably, among T2G3, T3G3, and T4G3 patients with lymph node metastasis, 96.9%, 93.6%, and 84.9% of patients had metastases exclusively below the iliac bifurcation, whereas 100%, 95.7%, and 95.9% had metastases exclusively below the aortic bifurcation, respectively. Multivariate logistic regression confirmed T-stage (odds ratio, 2.766; 95% CI, 2.347-3.259; P < .001) and G-grade (odds ratio, 3.794; 95% CI, 1.874-7.681; P < .001) as independent predictors of PLNM, with no significant associations observed for age, sex, or tumor size. We present a detailed map of PLNM in patients with bladder urothelial carcinoma with different T-stages and G-grades. The internal iliac/obturator packages appear to be most commonly involved. These findings demonstrate the significant impact of T-stage and G-grade on both the incidence and extent of PLNM. Collectively, these results may support future personalized treatment tailored to tumor stage and grade.