Clinical risk-based associations of lymph node dissection and detection of metastasis among men treated with radical prostatectomy.

Abstract

284 Background: Pelvic lymph node dissection (PLND) is recommended for most men at risk for lymph node involvement at the time of radical prostatectomy (RP) yet is frequently omitted. We aimed to examine the probability of PLND based on clinical risk status, and evaluate the impact of increasing lymph node yield on cancer detection rate across risk strata. Methods: We queried the National Cancer Database from 2004 to 2014 to identify patients with clinically localized PCa who underwent RP as their primary treatment. We extracted patient clinical and sociodemographic variables. Risk status was assessed using UCSF Cancer of the Prostate Risk Assessment (CAPRA) score. We fit conditional logistic regression models to estimate likelihood of PLND and incremental value of increasing lymph node count by risk strata. Results: We identified 698,728 men with PCa treated with RP including 380.201 (54.41%) whit PLND. Mean age at diagnosis was 62.6. PLND was omitted (Nx) in 56.1% of patients with low CAPRA-risk disease, 31.44% with intermediate and 24.72% high. Proportion of patients with >30 lymph nodes removed decreased from 9.3% on 2004 to 3.64% on 2014. Adjusting for clinical and pathologic factors, treatment in a community versus academic (Odds Ratio, OR=1.62, 95% CI 1.59-1.66; P <0.001) and black race (OR=1.13, 95% CI 1.09-1.17, P: 0.01) was associated with pNx status. Increasing lymph node count was independently associated with greater likelihood of detection of lymph node metastasis in all risk strata (11-20 nodes: OR: 3.13 , 95% CI 2.90-3.37, P<0.001; 20-30 nodes: OR: 5.07 , 95% CI 4.50-5.73, P<0.001; >30 nodes OR: 6.58, 95% CI 5.38-8.05, P<0.001) including patients with CAPRA-0 (11-20 nodes: OR: 3.28 , 95% CI 3.06-3.53, P<0.001; 20-30 nodes: OR: 5.77, 95% CI 5.16-6.45, P<0.001; >30 nodes OR: 7.90, 95% CI 6.56-9.51, P<0.001). Conclusions: PLND continues to be omitted in a substantial proportion of intermediate and high risk patients. Increasing lymph node yield was associated with greater odds of detecting lymph node metastasis in all groups of patients, including those at the lowest level of risk by clinical criteria.