Dynamic sentinel node biopsy for penile cancer: Reliability of a staging technique

Purpose: We determine the value of dynamic sentinel node biopsy for staging squamous cell carcinoma of the penis. Materials and Methods: A total of 90 patients with clinically node negative penile cancer were prospectively entered in this study. Preoperative lymphoscintigraphy was performed after intradermal injection of (99m)technetium nanocolloid around the primary tumor. The sentinel node was intraoperatively identified with the aid of intradermal administered patent blue dye and a gamma ray detection probe. Histopathological examination of sentinel nodes included serial sectioning and immunohistochemical staining. Regional lymph node dissection was performed only if metastasis was found in a sentinel node. Median followup was 36 months (range 5 to 95). Results: Lymphoscintigraphy visualized 217 sentinel nodes in 159 inguinal regions of 88 patients. A total of 208 sentinel nodes were intraoperatively identified in 149 inguinal regions of 88 patients. Sentinel node metastasis was found in 19 inguinal regions of 18 patients. Four of 8 patients with unilateral clinical stage N1 disease had a tumor positive sentinel node on the opposite site. Regional recurrence after excision of a tumor negative sentinel node or after nonvisualization was seen in 5 patients, resulting in a false-negative rate of 22% (5 of 23). The 3-year disease specific survival was 98% and 71% for patients with a tumor negative or tumor positive sentinel node, respectively (p = 0.0018). Conclusions: Occult lymph node metastases in penile cancer can be detected with a sensitivity of about 80% by dynamic sentinel node biopsy, including preoperative lymphoscintigraphy, vital dye and a gamma ray detection probe.