Lymph node yield as a predictor of overall survival following inguinal lymphadenectomy for penile cancer

To determine whether a specific lymph node yield (LNY) affects overall survival (OS) in patients with penile cancer.

Using the National Cancer Database, we identified 364 men diagnosed with pSCC who underwent ILND between 2004 and 2013. Men diagnosed on autopsy or at the time of death, patients with preoperative chemotherapy or radiotherapy, M+ and N3 disease, or with less than 3-month of follow-up were excluded. Kaplan-Meier analysis was used to compare Overall Survival (OS). A multivariable Cox regression model was developed to assess predictors of OS.

The median number of LN retrieved was 16 (IQR: 9-23). There was no significant difference in race, stage, grade for men with LNY ≤15 vs. >15. However, men with LNY ≤15 were significantly older than those with LNY >15 (65 vs. 59 years, p<0.001). On multivariable analysis, radical surgery, age, N+ disease, and LNY ≤15 were independent predictors of worse OS. Patients with LNY ≤15 showed significantly worse 5-year OS versus those with LNY >15 (49% vs. 67%, p=0.008). Nodal density (ND) ≥12.5% was also associated with decreased 5-year OS versus ND <12.5% (31% vs. 70%, p<0.0001).

LNY following ILND for pSCC appears to be an independent predictor of OS. A total LNY of >15 following ILND may have a beneficial impact on OS and serve as the threshold for defining an adequate ILND.