Sentinel lymph node biopsy using dynamic lymphoscintigraphy combined with ultrasound-guided fine needle aspiration in penile carcinoma

The purpose of this study was to assess the utility of sentinel lymph node lymphoscintigraphy (SLNL) and ultrasound-guided fine needle aspiration cytology (FNAC) in patients with penile carcinoma. A prospective study was undertaken of 64 patients with stage T1 (or greater) clinically NO squamous cell carcinoma of the penis. Patients underwent SLNL and bilateral groin ultrasonography with or without FNAC. Following intradermal blue dye, patients underwent unilateral or bilateral sentinel lymph node excision biopsy (SNB). 17 patients had sentinel nodes that contained metastases (21 nodal basins). Lymphatic drainage was demonstrated in all patients by lymphoscintigraphy. Bilateral drainage was seen in 57/64 patients. 61/64 patients had ultrasonography of the inguinal basins on the same day as FNAC of 38 basins. FNAC showed malignancy in eight basins. FNAC was negative in six basins, which were subsequently shown to be positive following SNB. 82 inguinal basins did not warrant FNAC by ultrasound criteria, of which 5 contained metastases at SNB. The sensitivity and specificity of ultrasonography was 74% and 77%, respectively. The positive and negative predictive values were 37% and 94%, respectively. Two patients had a negative initial SNB; however, ultrasonography identified a metastatic node and re-evaluation of the sentinel node confirmed micro-metastases. There has been no evidence of recurrence in any patients with negative SNB (during 6-28 months' follow-up). in conclusion, when investigating clinically stage NO penile cancer, the combination of SNB and groin ultrasonography, with or without FNAC, identifies accurately those with occult nodal metastases. Ultrasonography alone is not adequate as a staging technique, and SNB alone might miss between 5% and 10% of metastases.