Diagnostic accuracy of dynamic sentinel lymph node biopsy for penile cancer in men with non-palpable and palpable inguinal lymph nodes

Abstract

Introduction & Objectives: Penile cancer undergoes a stepwise dissemination and metastasises first to the inguinal lymph nodes (ILN). Because men can be cured in this early stage of metastatic disease, early detection and treatment is important. Materials & Methods: We performed a retrospective analysis of men with ≥T1G2 penile cancer and negative inguinal US guided FNA undergoing DSNB. Men with suspicious US but negative FNA underwent US guided ILN excision. Men with ≥T1G2 local recurrence during follow-up and non-squamous cell histologies were excluded. Descriptive analysis was performed, and sensitivity and negative predictive values (NPV) were calculated. Results: Of 1074 penile cancer treated between 2006-2020 a final cohort of 403 men with a median age of 65 years (interquartile range (IQR) 55-73) and body mass index (BMI) of 28.6 kg/m² (IQR 25-33) were included for this analysis. This gave 728 groins with negative FNA undergoing DSNB +/- US guided lymph node excision. At least one sentinel node (SN) was visualised in 93% during the 1st and in 7% during the 2nd lymphoscintigraphy. Median SNs visualised preoperatively was 1 and a median of 2 nodes were resected. ILN metastases were detected in 9% groins with non-palpable and in 17% with palpable lymph nodes. Stratified by non-palpable and palpable ILN, non-local recurrence despite pathologically negative DSNBs was observed in 0.5% and 0%. Limited to men with at least 24 months follow-up, non-local recurrence after negative DSNBs was observed in 0.4% and 0%. The sensitivity of DSNB was 96% and NPV was 100%. The main limitation of this analysis is its retrospective nature with inherit biases. Conclusions: Our results suggest that in a high volume centre pre-operative ultrasound +/- FNA and DSNB can be used to accurately stage men with non-palpable and palpable ILN in men with ≥T1G2 penile cancer. Further, FNA in advance of surgery provides logistical and surgical advantages. In those patients with palpable disease but negative FNA, we advocate ultrasound guided excision in case of enlarged or suspicious ILN during DSNB