RELIABILITY AND SAFETY OF DYNAMIC SENTINEL NODE BIOPSY (DSNB) IN CLINICALLY NEGATIVE INGUINAL NODES PENILE SQUAMOUS CELL CARCINOMA (SCC).
Early detection of inguinal node metastases from penile squamous cell carcinoma (SCC) is mandatory. Inguinal lymph-node dissection (ILND) represents the standard management of nodal disease, but it is conditioned by severe morbidity. According to EAU guidelines ILND is advised in patients with invasive and/or high grade cancer (≥pT1G2). In high volume centers dynami sentinel node biopsy (SNB) is performed to select patients for ILND in order to limit morbidity. This study analyzed data about patients with penile SCC and clinically negative inguinal nodes (cN0), stated by physical and ultrasound examination. The aim of the study is to assess the false negative rate, negative predictive value (NPV) and sensitivity, as well as complications of SNB procedure.
Methods and results
From 01-2000 to 12-2013, 110 patients (pts) underwent DSNB: 21 pts had clinical groin metastasis on one side and were not considered n this study. 89 patients (mean age 59 years, range 21-80) with penile squamous cell carcinoma pT1-3 clinically bilateral N0 (cN0) were retrieved from our prospectically kept database. The lymphoscintigraphy was performed the day of the surgery to identify the inguinal sentinel nodes which was intraoperatively detected by gamma probe and blue dye detection and then removed. In 76 out of 89 patients SNs were removed in both inguinal groin successfully. In 12 pts DSNB was performed in one groin only and in 1 patients SN was not bilaterally identified due to absent visualization during lymphoscintigraphy or low signal at the gamma probe during surgical procedure. Consequently SN was not identified (cNx) in 14 out of 178 inguinal groins (7.8%), while the procedure was completed in 164/178 (92.2%) groins. In 11/164 groins (6.7%) we had positive sentinel node, which was followed by ILND: 6 had pN1 (SN was the only one pathologic node), 5 pN2-N3 disease (TNM 2002) . After a median follow-up of 11 months (range 2-26 months) 12 out of 153 (7.8%) groins with negative SNB developed inguinal metastases; these pts underwent to radical nodal surgery: 2 pts had pN1, 6 pts pN2 and 2 pts pN3 (2 pts had bilateral positive groins). 3/14 groins (21.4%) without SN identification had positive nodes: 1 pN1 underwent ILND at the same time of DSNB, 2 pN2 at follow-up (2 and 13 months). Overall, we recorded 26/178 affected groin (15%). As a whole ILND could be spared in 85% of groins (152/178). On the other hand the false negative rate was 7.3% (12/164) leading to a relatively good NPV of 86% (141/164), but to a fair sensitivity of 48% (11/23). The efficiency rate of the whole procedure (considering all 178 groins we intended to explore) is even lower as we detected only 11/26 (42.3%) of the metastatic groins. We did not find majors complications. One pt developed an unusual intradermic metastatic spread, theoretically due to lymphatic drainage alteration after DSNB.
ILND represents the gold standard management for patients with nodal metastases or at risk of metastases from penile SCC. Nevertheless, DSNB is a safe procedure with limited major complications which was able to spare ILND to 85% of our patients: the NVP was 86% and sensitivity 48%. The efficiency rate of the intention to diagnose was even lower, as only 42% of metastatic nodes could be early detected. Special attention is mandatory in case of lack of groin signal following the injection of the radiotracer and a follow-up is advise also in case of negative bilateral sentinel node biopsy. The DSNB is a multistep procedure which requires accurate selection of patients and precise execution of the manouvres.
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