MP46-11: Bilateral inguinal lymphnode dissection versus inguinal lymphnode dissection and dynamic sentinel node biopsy in clinical N1 squamous cell carcinoma of the penis

Sebastiano Nazzani*, Mario Achille Catanzaro, Alberto Macchi, Tullio Torelli, Silvia Stagni, Antonio Tesone, Alice Lorenzoni, Mauro Maccauro, Rodolfo Lanocita, Tommaso Cascella, Davide Biasoni, Luigi Piva, Roberto Salvioni, Nicola Nicolai, Milan, Italy

Introduction: To evaluate the safety and efficacy of ipsilateral radical lymph node dissection (ILND) plus contralateral dynamic sentinel node biopsy (DSNB) vs bilateral ILND in clinical N1 (cN1) penile squamous cell carcinoma (peSCC) patients.

Methods: Within our institutional database (1980–2020, included), we identified 61 consecutive cT1-4 cN1 cM0 patients with histological confirmed peSCC who underwent either ipsilateral ILND plus contralateral DSNB or bilateral ILND. First, patients were stratified according to treatment (ipsilateral ILND plus contralateral DSNB or bilateral ILND). Second, patients’ groins were divided in 61 clinical positive (cN1) and 61 clinical negative (cN0) according to clinical nodal disease to separately analyze the risk of pathological disease according to clinical status. Third, patients were stratified according to presence or absence of disease in the cN0 groin to better understand potential differences between patients with unilateral vs bilateral disease. Fourth, Kaplan-Meier plots illustrated inguinal relapse (IR) rates and cancer specific survival (CSS) rates according to ipsilateral ILND plus contralateral DSNB or bilateral ILND.

Results: Median age was 54 years [Interquartile range (IQR): 48-60 years). Median follow-up was 68 months (IQR 21-105 months). Most patients had pT1 (23 %) or pT2 (54.1%), as well as G2 (47.5%) or G3 (23%) tumors, while lymphovascular (LVI) invasion was present in 67.1% of cases. Median clinical nodal volume was 20 mm (IQR 18, 30 mm). Ipsilateral ILND plus contralateral DSNB patients were older than bilateral ILND patients (63 vs 54 years old, p-value 0.039) and they had more frequently organ sparing surgery (26.9 vs 2.9%, p-value 0.023). Considering a cN1 and a cN0 groin, overall 57 out of 61 patients (93.5%) had nodal disease in the cN1 groin. Conversely, only 14 out of 61 patients (22.9%) had nodal disease in the cN0 groin. After stratification according to presence or absence of pathological disease in the cN0 groin (cN0pN+ vs cN0pN0) , cN0pN+ patients had tumor stage higher than pT1 in 92.8% of cases vs 57.4% of cN0pN0 patients (p-value 0.1). Moreover LVI was present in 92.9% vs 70% of cN0pNplus vs cN0pN0 patients (p-value 0.08). Finally, in survival analyses, 5-year IR-free survival was 91% [Confidence interval (CI) 80-100%] for bilateral ILND group and 88% (CI 73%-100%) for the ipsilateral ILND plus DSNB group (p-value 0.8). Conversely, 5-year CSS was 76% (CI 62-92%) for bilateral ILND group and 78% (CI 63%-97%) for the ipsilateral ILND plus contralateral DSNB group (p-value 0.9).

Conclusions: In patients with cN1 peSCC the risk of occult contralateral nodal disease is comparable to cN0 high risk peSCC. In consequence, the gold standard, namely bilateral ILND, may be replaced by unilateral ILND and contralateral DSNB without affecting positive node detection, IRs and CSS.

Source of Funding: None