MP57-16: Impact of Extent of Lymphadenectomy on All Cause Mortality in Patients with Intermediate and High-Risk Prostate Cancer Managed with Radical Prostatectomy

Furkan Dursun*, Ahmed Elshabrawy, Hanzhang Wang, Michael A. Liss, Ronald Rodriguez, Dharam Kaushik, Ahmed M. Mansour, San Antonio, TX

Introduction: The role of limited versus extended pelvic lymph node dissection (PLND) in the surgical management of prostate cancer (PCa) remains controversial. We sought to evaluate the impact of the extent of PNLD on survival outcomes for patients with intermediate and high-risk PCa.

Methods: The NCDB was queried for patients with intermediate and high-risk PCa (according to AUA guidelines risk stratification), who were treated by radical prostatectomy (RP) and PLND from 2004 to 2013.  We limited our cohort to men <70 years of age with a CCI=0. Patients were divided into 3 groups according to the  number of excised LN as a surrogate for the extent of PLND (Group 1:1–9, Group 2:10–19, and Group 3:=20 nodes).  Primary outcome  was overall survival (OS). All-cause mortality was evaluated using propensity score weighted Kaplan-Meir (KM) Curves and Cox regression models.

Results: 103,250 men had a new diagnosis of PCa, and 25.8% of those had high-risk PCa. The number of LN excised was <10 for 80.5%, 10-19 for 15.9%, and =20 for 3.6% of the patients. Figure 1 illustrates the KM curves in the propensity score-weighted cohorts. In intermediate-risk PCa patients, propensity score adjusted cox regression analysis showed OS benefit for group 2 compared to group 1 (HR0.86, CI0.79-0.93, p<0.001).  Similarly, in high-risk patients, group 3 had better OS compared to group 1 (HR0.61, CI 0.47-0.78, p<0.001) (Table1). pN+ disease rates were significantly higher in group 3 compared to group 1 and 2 in both intermediate and high-risk diseases. (Intermediate risk 9.3% vs. 1.5% and 4.5%, p<0.001; high risk 25.3% vs. 5.7%  and 15.5%,  p < 0.001, respectively)

Conclusions: Removal of =20 LNs during RP was associated with better OS for men with high-risk PCa. Similar survival benefit was noted in the intermediate-risk group with removal of 10-19 lymph nodes. Increased number of removed nodes was associated with increased likelihood of lymph node positivity and more accurate pathologic staging.

Source of Funding: None