Analysis of regional lymph nodes in periprostatic fat following robot-assisted radical prostatectomy

OBJECTIVE To determine the incidence and significance of lymph nodes in the anterior prostatovesicular lymphofatty tissue. PATIENTS AND METHODS One hundred and twenty patients with clinically localized prostate cancer underwent robot-assisted laparoscopic radical prostatectomy with excision of anterior prostatovesicular tissue at a single institution over a 6-month period. Tissue was sent for pathological analysis. Separate pelvic lymph node dissection was carried out in moderate-risk and high-risk patients. RESULTS A total of 20 out of 120 patients (16.7%) had lymph nodes in the anterior lymphofatty tissue. Average lymph node number when present was 1.5 (one to three). Pathological assessment of the lymph nodes revealed metastatic prostate cancer in 3 out of 120 (2.5%) patients, each of whom had adverse pathological features. Patients with metastatic lymph nodes in the anterior tissue did not have cancer involvement of the pelvic lymph nodes. Patients with lymph nodes found in the anterior lymphofatty tissue were slightly younger but were otherwise similar with respect to other demographics, prostate-specific antigen, biopsy Gleason score, clinical stage, pathological stage, pathological Gleason score, seminal vesicle invasion, and margin status. CONCLUSIONS Anterior lymphofatty tissue overlying the prostate occasionally contains lymph nodes that can harbour malignant disease and routine excision may eradicate regional tumour burden. Of patients with nodes, 15% were found to have malignant involvement. The long-term impact on progression-free and overall survival requires further study.