Assessing the density of lymph node metastasis in various inguinal regions of penile cancer using the nine-section method: A prospective study.

Inguinal lymph node (ILN) metastasis in patients diagnosed with penile squamous cell cancer (PSCC) is a notable factor that leads to a substantial decrease in patient survival rates. Current guidelines differ in terms of the scope of radical ILN dissection (rILND) and a unified consensus has not yet been reached. The present study aimed to optimize the standardized surgical lymph node dissection boundaries for rILND and to explore the rILND range suitable for the population. This prospective study included 26 patients with PSCC who underwent rILND. Anatomically, the ILNs were divided into 9 regions centered on the saphenofemoral junction and the bifurcation of the great saphenous vein, and a detailed pathological examination was performed. Positive ILNs were mainly concentrated in regions 1 and 2; however, 9.1% of positive ILNs were found in the surrounding regions 3, 4 and 7. Region 1 had the highest lymph node metastatic density among all regions. In patients with single or regional lymph node metastasis, positive ILNs were detected in regions 1, 2, 5 and 8. The pathway of ILN metastasis may first invade regions 1, 2, 5 and 8 and subsequently spread to other areas. Region 1 positivity was preliminarily associated with inferior disease-free survival but was not associated with overall survival. A detailed distribution map of ILNs with metastatic density using the nine-section method was established and an optimized dissection range was formed including region 1. This study was registered with the Chinese Clinical Trial Registry under clinical trial number ChiCTR2200064529 (registration date, 2022-10-11).