How to avoid false-negative dynamic sentinel node procedures in penile carcinoma.

PURPOSE: Evaluation of the false-negative dynamic sentinel node procedures in penile carcinoma at our institute.

MATERIALS AND METHODS: Between January 1994 and February 2003, 123 patients with penile squamous cell carcinoma underwent dynamic sentinel node biopsy.

RESULTS: The sentinel node revealed metastasis in 28 (23%) of 123 patients. Regional recurrence after excision of a tumor-negative sentinel node or after nonvisualization was seen in 6 patients resulting in a false-negative rate of 18% (6 of 34). We assume that 1 false-negative case was due to tumor blockage, 3 to tumor blockage and rerouting, 1 to a pathological sampling error and 1 to a low radioactivity level in the sentinel node during surgery.

CONCLUSIONS: Based on the false-negative results, important adaptations have been made in the dynamic sentinel node biopsy procedure for penile carcinoma at our institute. Pathological analysis was extended by serial sectioning and immunohistochemical staining, and preoperative ultrasonography with fine needle aspiration cytology has been added. Furthermore, exploration of groin without visualized sentinel nodes and intraoperative palpation of the wound have been introduced.