Surgical templates for inguinal lymph node dissection in cN0 penile cancer: A comparative study

Abstract

Purpose: Modified and superficial inguinal lymph node dissection (MILD and SILD) are the 2 widely used templates for surgical staging of clinically node negative (cN0) penile cancer (PeCa); however, no previous reports have compared their outcomes. We compared these 2 surgical templates for oncological outcomes and complications.

Materials and methods: We retrospectively reviewed records of cN0 PeCa patients who underwent MILD/SILD at our cancer care center from January 2013 to December 2019. Patients who developed a penile recurrence during follow up were excluded from analysis of oncological outcomes. The 2 groups (MILD and SILD) were compared for baseline clinico-pathological characteristics. The primary outcome was the groin recurrence free survival (gRFS). Secondary outcomes included the false negative rate (FNR) and disease free survival (DFS) for both templates and also the post-operative wound related complication.

Results: Of the 146 patients with intermediate and high risk N0 PeCa, 74 (50.7%) and 72 (49.3%) underwent MILD and SILD respectively. The 2 groups were comparable with regards to the distribution of T stage, tumor grade and the proportion of intermediate and high-risk patients. At a median follow up of 34 months (47 for SILD and 23 for MILD), a total of 5 groin recurrences were encountered; all of them occurred in the MILD group. The gRFS and DFS for the MILD group was 93.2% and 91.8% respectively; while that for the SILD group was 100% and 94.4% respectively. Too few events had occurred to determine any statistically significant difference. The FNR for MILD and SILD was 26.3% and 0% respectively. The overall complication rate was significantly higher in the SILD group (46% vs 20.3%, p=0.001), especially for Clavien Dindo 3A complications.

Conclusion: MILD can fail to pick up micro-metastatic disease in a small proportion of cN0 PeCa patients, while SILD provides better oncological clearance with no groin recurrences. This oncological superiority comes at the cost of a higher incidence of wound-related complications.

Keywords: Inguinal lymph node dissection; Modified inguinal lymph node dissection; Node-negative; Penile cancer; Superficial inguinal lymph node dissection.