The isolated gamma probe technique for sentinel node penile carcinoma detection is unreliable.

PURPOSE: Penile carcinoma is a common disease in northeast Brazil. This paper shows the results of the use of isolated gamma probe and discusses the incidence of false negative rates.
MATERIALS AND METHODS: From July 2000 to September 2003, 27 newly diagnosed penile carcinoma patients (T1, T2, N0) were included in this prospective study. The isolated gamma probe technique uses the sodium phytate technetium as a tracer and inguinal scanning with probe and after identified the lymph node it is removed. Lymphadenectomies were performed for positive inguinal lymph nodes metastasis.
RESULTS: There were 27 patients (mean age 59.6). Follow up was 37 months. Patients from country were 72% and illiterate or semi-illiterate were 56.7%. The tumors were mostly located in the glans (81.4%). They were T1, 52 % and T2, 48 %. 81.4% of the patients underwent partial penectomy, and 18.6% underwent postectomy and excision with wide margins. In 48% of the patients, the highest radioactive count rate was located on the left side, while in 41% was located on the right side. Only one patient had a positive pathological lymph node metastasis at the moment of the surgery. Additionally 3 patients became inguinal lymph node positive at the follow up. This date yielded a sensibility rate of 25% and a false-negative rate of 42.8%.
CONCLUSION: Isolated gamma probe technique for sentinel node penile carcinoma has a very low sensibility and a high false negative rate. Therefore it is highly advisable the addition of others methods such as lymphoscintigraphy, vital blue, ultrasonography and so on. The isolated gamma probe technique for sentinel node penile carcinoma detection is unreliable.