Sentinel lymph node in prostate carcinoma: Methodology, feasibility, surgical, and oncological consequences, about 74 patients.

Abstract

e15109 Background: There are few studies in the field of prostatic sentinel lymph node (SLN) procedure: in the international literature at the most 10 publications are found. However the interest of urological surgeons and oncologists is growing fast. Goals of our study were: on the first hand to evaluate the rate of SLN SPECT-CT detection and the rate of SLN involvement, on the other hand to evaluate the incidence of the SLN biopsy results on the surgical and oncological management. Methods: 74 patients with prostate cancer were included. All patients had a Gleason score between 6 and 8. All patients were elected for a radical laparoscopic prostatectomy. Nanocis-Tc 99m was intratumorally injected, guided by transrectal ultrosonography. 2 injections of 0.6 ml in each lobe of the prostate were performed, depending on the size of the prostate. Patient underwent planar imaging and SPECT-CT 2 hours after injections. Surgery was performed 18 hours after SPECT-CT lymphoscintigraphy. Results: A lymphatic pelvic drainage was seen in 94,6 % (70/74) by SPECT-CT. Lymphatic drainage was on the right side (23), on the left side (15), or bilateral (32). The radioguided lymphadenectomy was assisted by a laparoscopic gamma-probe, the SLN detection rate was 97% (68/70); the average number of resected radioactive nodes was 1.6 (range 1 to 5). By all the ways, a limited pelvic lymph node dissection was performed in all 74 cases. An SLN involvement was found in 5 cases (5/68= 7.35%); in these 5 cases and in the 63 cases without SLN involvement, no metastatic involvement was found in the other lymph nodes, as well as in the 6 patients for which no SLN could be selectively resected (4 with no drainage seen and 2 not detected intra-operatively although visualized on lymphoscintigraphy). Conclusions: The low rate of lymphatic involvement is not surprising considering the Gleason score range 6 to 8 (low metastatic risk). So, the preliminary results are very attractive, especially for these patients that could have been falsely considered as N0. Our study is still in progress, and if these results are confirmed on a larger scale, then SLN procedure could be considered in the routine management of low risk prostatic carcinomas.