Effect of inguinal lymph node dissection in lymph node negative patients with squamous cell carcinoma of the penis

Introduction The survival benefit of inguinal lymph node dissection (ILND) vs no ILND in patients with squamous cell carcinoma of the penis (SCCP) and the absence of lymph node invasion is unclear. We addressed this uncertainty within the Surveillance, Epidemiology and End Results (SEER 2000-2018) database. Material and methods We identified lymph node negative SCCP patients who either underwent ILND (pN0) or clinical examination only (cN0). We tested for the effect of ILND vs no ILND on cancer-specific mortality (CSM) in Kaplan-Meier plots, univariable and multivariable Cox regression analyses, in a pT stage-specific fashion, before and after 1:3 propensity score matching (PSM). Sensitivity analyses were conducted according to historical and contemporary treatment periods as well as geographic regions. Results Of 2520 SCCP patients, 369 (15%) underwent ILND (pN0) vs 2151 (85%) did not (cN0). The pN0 vs cN0 distribution according to pT stages was as follows: 80 (7%) vs 1092 (93%) in pT1b, and 289 (21%) vs 1059 (79%) in pT2-3. At 36 months, CSM-free survival in pT2-3 stage was 89% in ILND vs 74% in no ILND patients (multivariable hazard ratio: 0.42, CI 0.30-0.60, p < 0.001). This result was confirmed in sensitivity analyses, and after 1:3 PSM. The same analyses could not be completed in pT1b stage due to insufficient number of observations and events. Conclusions In pT2-3 stage SCCP, a significantly lower CSM was recorded in lymph node negative patients treated with ILND than in their clinical lymph node negative counterparts who did not undergo ILND.