Prognostic significance of lymph node yield in pelvic lymph node dissection for bladder cancer: population-based study

Radical cystectomy (RC) with neoadjuvant chemotherapy (NAC) and pelvic lymph node dissection (PLND) is standard for muscle-invasive bladder cancer (MIBC). While PLND improves staging and local control, the optimal extent is debated. This study used the SEER database (2000–2021) to evaluate lymph node yield's (LNY) prognostic significance. We included 12,698 patients who underwent PLND, stratified by LNY quartiles (cutoffs at 12, 19, and 29). Inverse probability of treatment weighting (IPTW) was applied to balance baseline characteristics. Cox regression, Kaplan–Meier curves, and competing risk models assessed the impact of LNY on overall survival (OS) and cancer-specific survival (CSS). A prognostic nomogram incorporating LNY was developed and validated using LASSO regression, the area under the curve (AUC) and calibration plots. The optimal threshold for LNY was determined to be 12, with LNY ≥ 12 associated with a 17% reduction in all-cause mortality risk (HR 0.83, 95% CI 0.79–0.88). An increase in LNY was correlated with improvements in OS and CSS, with the 5-year OS rate increasing from 46.0% to 55.6%. A nonlinear relationship between LNY and all-cause mortality risk was observed, as the protective effect diminished after exceeding 39. This study supports the establishment of LNY threshold of 12 as an indicator of surgical completeness; an LNY of 20–39 may be associated with a sustained protective effect. However, excessive LNY may not yield additional benefits. Clinical decision-making should consider patient characteristics and healthcare accessibility to optimize outcomes for bladder cancer. 1. The lymph node yield (LNY) threshold of 12 is associated with differences in long-term prognosis for bladder cancer. 2. Populations with better healthcare access may further benefit from increased LNY. 3. An LNY of 20-39 is associated with a sustained protective effect, while an LNY exceeding 39 may lead to an increased risk of all-cause mortality.