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

• To determine the incidence and significance of lymph nodes in the anterior prostatovesicular lymphofatty tissue.

• 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.

• 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.

• 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.