Laparoscopic Pelvic Lymph Node Dissection for Prostate Cancer

Pelvic lymphadenectomy unquestionably is still the most accurate method to identify the presence or absence of lymphatic extension of prostate cancer. Lymphatic spread follows the lymph channels that leave the prostate posteriorly and then spread primarily to a lymphatic field of drainage that includes the perivesical, hypogastric, obturator, presacral, and presciatic lymph nodes. The obturator nodes are commonly the first site of meta~tasis.~' The risk of nodal involvement is increased with larger tumor volume and local periprostatic spreadlo; however, when only the histopathologic grade of the tumor is used, no method is precise in detecting positive pelvic lymph nodes with increasing Gleason score.2,18,22,28 At present, no imaging modality can identify accurately lymphatic involvement with prostate cancer. The role of CT scan in evaluating lymph node involvement is limited, with an accuracy rate of only 65%.3 In addition, microscopic nodal metastases cannot be demonstrated by CT scan in patients with advanced disease of the prostate (stages B,, C, or D).15,32 Unless the nodes are grossly enlarged, CT scan imaging of the prostate is limited as a staging tool for prostate cancer. The value of ultrasonography and magnetic resonance imaging for pelvic lymph node involvement is similar to that of CT scan, with a reported accuracy of 84% to 89%:~~~ Pedal lymphangiography, Color reproduction in this article courtesy of a grant by Tap Pharmaceuticals, Inc.