Robotic inguinal lymphadenectomy for penile cancer: the why, how, and what
Squamous cell carcinoma of the penis (SCC-P) demonstrates a reliable pattern of spread to the lymph nodes of the groin. High grade and higher stage (pT1b or greater) SCC-P demonstrate a higher propensity for metastasis to the inguinal lymph nodes. Further, lymphadenopathy progresses in a predictable fashion, from superficial inguinal lymph nodes to deep inguinal lymph nodes to pelvic lymph nodes, with limited survival noted for those patients with progression to pelvic lymph nodes. Fortunately, inguinal lymphadenectomy can provide cure and improvement in RFS for SCC-P. Unfortunately open inguinal lymphadenectomy is associated with significant morbidity. Perhaps owing to this morbidity, inguinal lymphadenectomy is underperformed in the US. In other words, urologists only offer inguinal lymphadenectomy for high risk SCC-P in only a minority of cases and even when performed, lymph node yield is often unsatisfactory (less than 8 nodes per groin). Recently, a laparoendoscopic inguinal lymphadenectomy has been developed as a new approach to offer potentially curative lymph node resection while minimizing morbidity. The robotic platform has since been adapted for this approach and several reports demonstrate significant improvements in morbidity while maintaining oncologic equivalency. This review highlights the rationale for inguinal lymphadenectomy, inguinal lymph node anatomy, and technical considerations and outcomes of laparoscopic and robotic inguinal lymphadenectomy.