Dynamic Sentinel Lymph Node Biopsy for Penile Cancer: Accuracy is in the Technique

Abstract

Objectives: To demonstrate an operative standard for dynamic sentinel lymph node biopsy (DSLNB). Long-term survival in men with penile squamous cell carcinoma (SCC) depends on accurately staging lymph node metastases. European Association of Urology (EAU) and National Comprehensive Cancer Network (NCCN) guidelines recognize DSLNB as a standard for staging men with intermediate to high-risk tumors and clinically absent inguinal lymphadenopathy. DSLNB accuracy has been linked with pre-operative planning and surgical technique, yet no peer-reviewed video exists to establish an operative standard. Here we present a narrated video of our technique and discuss the accuracy of this approach using retrospective patient data.

Methods: Ethics approval and patient consent was obtained. Retrospective analysis was performed on patients undergoing DSLNB for inguinal lymph node staging of histologically proven penile SCC. Data was included from 2 experienced uro-oncologists with subspecialty training in penile cancer working in Victoria, Australia between January 2015 and July 2021. Variables collected included Primary tumour histology, DSLNB pathology, progression to radical inguinal lymph node dissection (RILND) and recurrence patterns. DSLNB sensitivity and proportion of groins spared RILND is calculated.

Results: DSLNB was performed on 127 groins (64 patients) during the study period. Within the cohort, 44% (n = 28) of patients had a pre-operative lymphoscintigraphy with single-photon emission computed tomography (SPECT/CT). Analysis of primary tumor intervention demonstrates that 82.8% (n = 53) of men underwent penile sparing surgery. Tumor histology in 88% of patients (n = 56) demonstrated pT1-pT2 disease. Overall n = 19 groins undergoing DSLNB were positive for malignancy and n = 108 were negative. 36 groins progressed to RILND during a mean follow up of 29 months. Only 2 groins that previously had a negative DSLNB were positive on RILND, one in the groin and one in the pelvis. We observed a false negative rate of 1.9% and a sensitivity of 90.5%. In our cohort DSLNB allowed 71.7% of groins to proceed for surveillance instead of prophylactic radical ILND.

Conclusions: DSLNB is a safe and accurate method for assessing inguinal lymphadenopathy in men with intermediate to high-risk penile SCC and impalpable groins. This video study establishes an operative standard for DSLNB with oncological outcomes are consistent with international expectations. Standardized use of DSLNB by an experienced team will reduce morbidity while maintaining oncological safety for men with intermediate to high-risk penile cancer and cN0 disease.