INTRAOPERATIVE USE OF GAMMA PROBE FOR IDENTIFICATION OF SENTINEL NODE IN PENILE CANCER

Purpose: Lymphatic mapping and intraoperative lymphoscintigraphy has become part of the management of melanoma and breast cancer with regard to both staging and treatment. We report our technique to detect the sentinel lymph node in patients with malignant penile lesions using a probe to detect pre- and intraoperative gamma radiation. Materials and Methods: A prospective study was initiated in July, 2000 for sentinel node identification using the gamma probe in 12 patients with T1, T2 and selected cases of T3, N0 or N1 penile cancer. Sodium fitate Technetium-99m-labeled was injected at the site of primary penile carcinoma 1/2 hour before surgery. The sentinel lymph nodes were located using the gamma probe and excised through a 2 cm inguinal incision. A full groin dissection was performed only in cases in which paraffin histopathologic examination of the node demonstrated metastasis. Results: Eleven sentinel nodes were identified by the gamma probe and excised. In 9 patients, the sentinel nodes were negative at the paraffin histopathologic examination. In 2 patients the sentinel node revealed metastasis focus. In both cases a full groin dissection was carried out which revealed no other nodal metastases. The patients with negative sentinel node are under surveillance at a 3-month interval. Only one patient developed inguinal metastases 3 months after the procedure. To date, ten patients, including the 2 patients with metastatic sentinel node, are free of the disease. Conclusion: The identification of the sentinel node by gamma probe may be useful to define the presence or absence of inguinal node metastasis in patients with T1, T2 and selected T3 penile cancer. This approach may spare many patients from inguinal lymphadenectomy, which is associated with long-term morbidity.