Feasibility of performing dynamic sentinel lymph node biopsy as a delayed procedure in penile cancer.

Introduction: Patients diagnosed with penile cancer and clinically impalpable inguinal lymph nodes (cN0), normally undergo dynamic sentinel lymph node biopsy (DSNB) at the same time as the primary penile surgery. The aim of this study is to investigate the diagnostic accuracy and clinical outcomes of performing DSNB in patients who have already undergone surgery for the primary penile cancer.

Methods: Ninety-two patients with unilateral or bilateral impalpable inguinal lymph nodes (LNs) who had already undergone primary resection of the penile tumour (stage ≥ T1G2) were included in this study. All patients underwent a preoperative USS of the groin(s) with fine needle aspiration cytology (FNAC). Provided that the FNAC was clear, DSNB was performed. Radical inguinal lymphadenectomy was performed if the histological analysis of the SLN confirmed the presence of micrometastatic disease.

Results: DSNB was undertaken in 165 groins with a nonvisualisation rate of 4.8 % (8/165 groins). The SLN was positive for micrometastatic disease in nine groins (5.5 %) from a total of eight patients (8.7 %). One patient developed regional recurrence in a prepubic LN after excision of bilateral negative SLN (1.1 %). The three-year disease-specific survival for patients with negative and positive SLN was 98.8 and 87.5 %, respectively (p = 0.042). Using DSNB, occult LN metastases in penile cancer can be detected with a sensitivity of 88.9 % and specificity of 100 %.

Conclusions: We have demonstrated that DSNB is feasible as a delayed procedure to localise the SLN. Surgical resection of the primary penile lesion does not appear to change the lymphatic drainage.