How safe is the modified pelvic lymphadenectomy in prostate cancer? Results of a new technique

Purpose: The goal of this study was to show lymphatic drainage and to verif y the validity of lymphoscintigraphy for the identification of the sentinel lymph node (SLN) in prostate cancer. Furthermore, the question is to be ra ised whether the standardized pelvic lymphadenectomy is a sufficient means for also detecting solitary micrometastases. Materials and Methods: 25 patients with prostate cancer received a sonograp hically controlled, transrectal administration of a technetium-99m colloid injected directly into the prostate one day prior to pelvic lymphadenectomy . 20 minutes-later the dynamic lymphoscintigraphy was carried out. During s urgery, the sentinel lymph nodes were identified by using a gamma probe. Th e standard pelvic lymphadenectomy was performed; after removal of the SLN. Results: In 7 of 8 patients with micrometastasis the spread of the tumor co uld exclusively be found in those nodes which had been identified as sentin el lymph nodes by mean; of this innovative diagnostic method for prostate c ancer. In 2 cases, the pathologically proved SLN were situated at the anter omedial region of the internal iliac artery, thus being located outside of the standard pelvic lymphadenectomy area. In 1 patient, however, the microm etastasis was found beyond those nodes which had been identified as SLN int raoperatively. Conclusions: Our first results suggest that pelvic staging lymphadenectomy might be restricted to those nodes having been identified als SLN by this m ethod. The extend and duration of surgery as well as perioperative morbidit y may be reduced by increasing the sensitivity of the detection of micromet astasis. Our data confirm earlier perceptions, according to which even modi fied standardized pelvic lymphadenectomy is considered insufficient in term s of the detection of all micrometastases.