Identifying an optimal lymph node yield for penile squamous cell carcinoma: prognostic impact of surgical dissection

Objective To evaluate the prognostic impact of lymph node yield ( LNY ) on survival outcomes for penile squamous cell carcinoma (SCC). Patients and methods In all, 532 patients who underwent inguinal LN dissection ( ILND ) across tertiary referral centres from Europe, China, Brazil and North America were retrospectively evaluated. From this cohort, 198 patients received pelvic LND ( PLND ).We identified threshold values for ILND and PLND using receiver operating characteristic curves. We tested prognostic value of LNY for recurrence‐free survival ( RFS ), disease‐specific survival ( DSS ), and overall survival ( OS ) using the Kaplan–Meir method and Cox proportional hazard regression models. Results The median (interquartile [IQR]) age was 59 (49–68) years and the median (IQR) follow‐up after ILND was 28 (12–68.2) months. Overall, 85% of the patients had bilateral dissections. The median (IQR) number of inguinal LN s removed was 15 (10–22). Of those receiving PLND , The median (IQR) number of LN s was 13 (8–19). A LNY of ≥15 was used for dichotomisation of ILND patients, and a LNY of ≥9 was used in the PLND cohort. Patients with a LNY ≥15 had significantly better 5‐year OS vs patients with a LNY <15 (70.1% vs 58.7%). On multivariable analyses, a LNY ≥15 was a predictor of OS ( hazard ratio [HR] 0.68, P = 0.029). For cN 0 patients, a LNY ≥15 was an independent predictor of RFS ( HR 0.52, P = 0.043) and OS ( HR 0.53, P = 0.021). In the PLND cohort, a LNY ≥9 was a predictor of RFS ( HR 0.53, P = 0.032). Conclusions Using one of the largest LND datasets to date, we found LNY to be a significant predictor of outcomes after lymphatic staging for penile SCC . Prospective validation is warranted.