Feasibility and Safety of Sentinel Lymph Node Biopsy in Localized Prostate Cancer

AIM. The presence of lymph-node (LN) metastases in prostate cancer (PCa) is an important prognostic factor with a great therapeutical relevance. As current imaging techniques cannot provide an accurate nodal staging, the lymphadenectomy is still the modality of choice for detecting LN metastases, though with varying extension. Aim of this study was to evaluate the feasibility and safety of nodal staging by sentinel LN (SLN) biopsy in patients (pts) with localized PCa. MATERIALS AND METHODSFrom October 2011 to February 2012 laparotomic SLN dissection was performed in 19 pts during radical prostatectomy. All pts (PSA range: 2 - 21 ng/ml; Gleason Score 5 - 8) had a localized PCa according to the standard staging diagnostic procedures. Twenty hours before surgery, 240 MBq of 99mTc Nanocoll® in 0.8 ml of physiological solution (divided into 4 injections of 60 MBq) were injected into the prostate gland under transrectal ultrasound guidance. A planar scintigraphy and a SPET/CT scan were performed 1-2h after the injection. SLNs detected by both studies were classified on the basis of the intensity of uptake and anatomic localization. Intraoperatively, all LNS detected by gamma-probe with an activity significantly higher than background (4 cps) were removed and classified as SLNs. Obturator LNs were removed in any case, even in the absence of activity, and classified as SLNs only if detected by gamma-probe. All SLNs were then evaluated by histological analysis. RESULTSThe intraoperative detection of SLNs occurred in all 19 pts, while the scintigraphic localization was observed in 18/19 pts. In 1/19 pt the abdominal bladder activity probably masked the SNL, that was however detected intraoperatively by gamma-probe. In 6/19 pts (31%) SLNs were exclusively outside the obturator fossa while in 13/19 pts (69%) SLNs were both inside and outside obturator fossa. A total of 56 SLNs wewe found. At histopathological analysis 4/56 SLNs resulted positive for metastases (2/19 pts): 3/4 were in the obturator fossa while the remaining SLN was in the internal iliac chain, that is not a routinely sampled region. All other dissected LNs resulted negative; the false negative rate was 0/19 (0%). No post-surgical complications were found in our population. CONCLUSIONSOur preliminary data confirm the feasibility and the safety of SLN biopsy in nodal staging of PCa. The intraoperatively SLN detection rate resulted 100%. In 1 patient a micrometastases was found outside of obturator fossa in a not routinely sampled site.